Thanks Gry,
But just adding that recaptcha code to the signup.tpl won't help in anyways. The register function has to be modified so that it reads the new code from the recaptcha and that's what i needed help with...

A good reference would be this: http://forums.pligg.com/pligg-mods/8033 ... ptcha.html

The guy has made a mod on how to use this for Pligg, similarly we can use that php file and just need to know how to modify the register code..thats all.

To add this to comments, we will have to modify the comments code then...same logic.