private void GetLatLongFromAddress(string street, string city, string state)
{
    string geocoderUri = string.Format(@"http://rpc.geocoder.us/service/rest?address={0},{1},{2}", street, city, state);
    XmlDocument geocoderXmlDoc = new XmlDocument();
    geocoderXmlDoc.Load(geocoderUri);
    XmlNamespaceManager nsMgr = new XmlNamespaceManager(geocoderXmlDoc.NameTable);
    nsMgr.AddNamespace("geo", @"http://www.w3.org/2003/01/geo/wgs84_pos#");
    string sLong = geocoderXmlDoc.DocumentElement.SelectSingleNode(@"//geo:long", nsMgr).InnerText;
    string sLat = geocoderXmlDoc.DocumentElement.SelectSingleNode(@"//geo:lat", nsMgr).InnerText;

    Latitude = Double.Parse(sLat);
    Longitude = Double.Parse(sLong);
}

http://dev.virtualearth.net/REST/v1/Locations/CA/adminDistrict/postalCode/locality/addressLine?includeNeighborhood=includeNeighborhood&key=BingMapsKey

http://dev.virtualearth.net/REST/v1/Locations/US/1125%20E.%20102nd%20Street,%20Los%20Angeles,%20CA?key=Ai9-KNy6Al-r_ueyLuLXFYB_GlPl-c-_iYtu16byW86qBx9uGbsdJpwvrP4ZUdgD

{
   "authenticationResultCode":"ValidCredentials",
   "brandLogoUri":"http://dev.virtualearth.net/Branding/logo_powered_by.png",
   "copyright":"Copyright © 2012 Microsoft and its suppliers. All rights reserved. This API cannot be accessed and the content and any results may not be used, reproduced or transmitted in any manner without express written permission from Microsoft Corporation.",
   "resourceSets":[
      {
         "estimatedTotal":1,
         "resources":[
            {
               "__type":"Location:http://schemas.microsoft.com/search/local/ws/rest/v1",
               "bbox":[
                  33.940492293415652,
                  -118.26180800227225,
                  33.948217728557005,
                  -118.24939194889963
               ],
               "name":"1125 E 102ND St, Los Angeles, CA 90002",
               "point":{
                  "type":"Point",
                  "coordinates":[
                     33.944355010986328,
                     -118.25559997558594
                  ]
               },
               "address":{
                  "addressLine":"1125 E 102ND St",
                  "adminDistrict":"CA",
                  "adminDistrict2":"Los Angeles Co.",
                  "countryRegion":"United States",
                  "formattedAddress":"1125 E 102ND St, Los Angeles, CA 90002",
                  "locality":"Los Angeles",
                  "postalCode":"90002"
               },
               "confidence":"High",
               "entityType":"Address",
               "geocodePoints":[
                  {
                     "type":"Point",
                     "coordinates":[
                        33.944355010986328,
                        -118.25559997558594
                     ],
                     "calculationMethod":"Parcel",
                     "usageTypes":[
                        "Display"
                     ]
                  },
                  {
                     "type":"Point",
                     "coordinates":[
                        33.944118499755859,
                        -118.25559997558594
                     ],
                     "calculationMethod":"Interpolation",
                     "usageTypes":[
                        "Route"
                     ]
                  }
               ],
               "matchCodes":[
                  "Good"
               ]
            }
         ]
      }
   ],
   "statusCode":200,
   "statusDescription":"OK",
   "traceId":"81518ba504a3494bb0b62bdb6aa4b291|LTSM002104|02.00.83.500|LTSMSNVM001473, LTSMSNVM001463, LTSMSNVM001452, LTSMSNVM001851, LTSMSNVM001458, LTSMSNVM001462"
}

http://dev.virtualearth.net/REST/v1/Locations/US/1125%20E.%20102nd%20Street,%20Los%20Angeles,%20CA?o=xml&key=Ai9-KNy6Al-r_ueyLuLXFYB_GlPl-c-_iYtu16byW86qBx9uGbsdJpwvrP4ZUdgD

<Response>
  <Copyright>Copyright ? 2012 Microsoft and its suppliers. All rights reserved. This API cannot be accessed and the content and any results may not be used, reproduced or transmitted in any manner without express written permission from Microsoft Corporation.</Copyright>
  <BrandLogoUri>http://dev.virtualearth.net/Branding/logo_powered_by.png</BrandLogoUri>
  <StatusCode>200</StatusCode>
  <StatusDescription>OK</StatusDescription>
  <AuthenticationResultCode>ValidCredentials</AuthenticationResultCode>
  <TraceId>b9af8a6b058b455ca9c368b9e32142fe|LTSM002102|02.00.83.500|LTSMSNVM002001, LTSMSNVM001464, LTSMSNVM001451, LTSMSNVM001452, LTSMSNVM001457, LTSMSNVM002052, LTSMSNVM001461</TraceId>
  <ResourceSets>
    <ResourceSet>
      <EstimatedTotal>1</EstimatedTotal>
      <Resources>
        <Location>
          <Name>1125 E 102ND St, Los Angeles, CA 90002</Name>
          <Point>
            <Latitude>33.944355010986328</Latitude>
            <Longitude>-118.25559997558594</Longitude>
          </Point>
          <BoundingBox>
            <SouthLatitude>33.940492293415652</SouthLatitude>
            <WestLongitude>-118.26180800227225</WestLongitude>
            <NorthLatitude>33.948217728557005</NorthLatitude>
            <EastLongitude>-118.24939194889963</EastLongitude>
          </BoundingBox>
          <EntityType>Address</EntityType>
          <Address>
            <AddressLine>1125 E 102ND St</AddressLine>
            <AdminDistrict>CA</AdminDistrict>
            <AdminDistrict2>Los Angeles Co.</AdminDistrict2>
            <CountryRegion>United States</CountryRegion>
            <FormattedAddress>1125 E 102ND St, Los Angeles, CA 90002</FormattedAddress>
            <Locality>Los Angeles</Locality>
            <PostalCode>90002</PostalCode>
          </Address>
          <Confidence>High</Confidence>
          <MatchCode>Good</MatchCode>
          <GeocodePoint>
            <Latitude>33.944355010986328</Latitude>
            <Longitude>-118.25559997558594</Longitude>
            <CalculationMethod>Parcel</CalculationMethod>
            <UsageType>Display</UsageType>
          </GeocodePoint>
          <GeocodePoint>
            <Latitude>33.944118499755859</Latitude>
            <Longitude>-118.25559997558594</Longitude>
            <CalculationMethod>Interpolation</CalculationMethod>
            <UsageType>Route</UsageType>
          </GeocodePoint>
        </Location>
      </Resources>
    </ResourceSet>
  </ResourceSets>
</Response>