Tmobile:
APN: wap.voicestream.com
username: n/a
password: n/a

First I found a proxy.pac file, (Just do a proxy.pac flie search on google or use mine) edited it in notepad (if you save as for testing make sure it does not save as proxy.pac.txt):

function FindProxyForURL(url, host)
{
if (isInNet(myIpAddress(), “10.0.0.0“, “255.0.0.0“))
return “PROXY 216.155.165.50:8080“;
else
return “DIRECT“;
}

Tmobile gives us 10.x.x.x addresses so I just told it to use the proxy when my address is that.

Next I saved this file in “/private/var/root“

Then I edited my preferences file located in: /private/var/root/Library/Preferences/SystemConfiguration/preferences.plist (I used wordpad) adding the following:

<dict>
<key>Interface</key>
<dict>
<key>DeviceName</key>
<string>ip1</string>
<key>Hardware</key>
<string>com.apple.CommCenter</string>
<key>Type</key>
<string>com.apple.CommCenter</string>
</dict>
<key>Proxies</key>
<dict>
<key>ProxyAutoConfigEnable</key>
<integer>1</integer>
<key>ProxyAutoConfigURLString</key>
<string>file:///private/var/root/proxy.pac</string>
</dict>
<key>com.apple.CommCenter</key>
<dict>
<key>AllowNetworkAccess</key>
<integer>1</integer>
<key>Available</key>
<integer>1</integer>
<key>Setup</key>
<dict>
<key>apn</key>
<string>gprs.qtel</string>
<key>password</key>
<string>gprs</string>
<key>username</key>
<string>gprs</string>
</dict>
<key>Version</key>
<integer>1</integer>
</dict>
</dict>