Some email providers limit the size or type of files that you can attach to email.
Dropload [1] and YouSendIt [2] are two services we found with good reviews that let you get around this problem.
Links:
[1] http://wwww.dropload.com
[2] http://www.yousendit.com
[3] https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&business=rick@yourpcpartner.com&item_name=Buy