How to work on Frames using selenium

It is not an easy talk to identify the frame name or ID..when the frame name is changing dynamically...
For example login in gmail and try to compose a mail...Compose mail button is kept in a separate frame..for the we need to select that frame...first we need to select that frame and later we need to click on that button..

i am searching for how to identify the frame..after gettign i will update the post....

****Will post soon******