An article at Military.com Resources suggests offering your Gmail invites to troops abroad.
At the moment, Google is in beta testing and is available by invitation only. Current users with Gmail accounts are given an opportunity to invite a limited number of friends to open a Gmail account. Those friends are later allowed to invite more friends to open an Gmail account and so on. Because troops abroad have a real use for these accounts, a Website — http://www.gmail4troops.com — is calling for those invitations to be used on troops abroad. Loved ones can send them large-size movies or photos without the need for those emails to later be deleted because of file size. If you have a Gmail invite to offer, Gmail4troops.com asks that you post it through them.
Nifty idea.