xbiff with Gmail (2 May 2013)
It is possible to use xbiff with Gmail. It involves fetchmail and IMAP.
Put this in your ~/.fetchmailrc:
poll imap.gmail.com protocol IMAP user "(insert username here)@gmail.com" there with password "(insert password here)" nofetchall keep ssl
Then have xbiff use this X resource:
XBiff*checkCommand: fetchmail -d0 -csk
I also recommend adding this resource to prevent it from checking so frequently:
Now xbiff should check your Gmail inbox. I prefer to use it in FvwmButtons.