The idea of being able to play chess via one's mobile is great...but how can I get it to work on my HTC.

Which HTC do you have. Model? Usually you go to the chess.com/mobile url on your mobile and this will ask you to install the apllication.

Sorted, thanks for the help!

I am unable to sign in on Mobile Chess on my Blackberry curve.  I put in name and password and it does nothing.  Help!

I have a Blackberry Curve and get this problem periodically for no apparent reason.  When it happens I just reinstall the mobile chess program and it works fine (until next time).  Not an elegant solution, I'll admit, but a solution 

Have you looked at this thread:

http://www.chess.com/forum/view/help-support/mobile-chess-on-bb-curve

It seems to solve a lot of Blackberry issues.