I've also been trying to log into gmail and it's stuck at "Checking" stage. Since this was my first time logging in, I wasn't sure if it's my connection or some software error, but it seems now others are also having issues.

Rebooting seems to fix it, for now.

A couple of similar threads I found while troubleshooting:
http://goo.gl/Lxh4a [nokia.com]
http://goo.gl/UkKF7 [nokia.com]