>>> email.utils.getaddresses(['[email protected], John Smith <[email protected]>,"Smith, Jane" <[email protected]>'])
[('', '[email protected]'), ('John Smith', '[email protected]'), ('Smith, Jane', '[email protected]')]

from email.utils import getaddresses

addrstring = ',[email protected], John Smith <[email protected]>,"Smith, Jane" <[email protected]>,'

def addrparser(addrstring):
    addrlist = ['']
    quoted = False

    # ignore comma at beginning or end
    addrstring = addrstring.strip(',')

    for char in addrstring:
        if char == '"':
            # toggle quoted mode
            quoted = not quoted
            addrlist[-1] += char
        # a comma outside of quotes means a new address
        elif char == ',' and not quoted:
            addrlist.append('')
        # anything else is the next letter of the current address
        else:
            addrlist[-1] += char

    return getaddresses(addrlist)

print addrparser(addrstring)

[('', '[email protected]'), ('John Smith', '[email protected]'),
 ('Smith, Jane', '[email protected]')]