M interesting in designing new scanning techniques specially for mails and web pages .. How Can I contribute ??

ClamWin use the clamav engine. If you are interested in the antivirus engine you should contact clamav developers:
https://www.clamav.net/
https://www.clamav.org/contacts/

I'm not sure that ClamAV will ever be interested in scanning Web pages. Some of the more progressive antivirus companies are now doing something along this line. I recall that AVG just bought out LinkScanner because it has technology that evaluates a Web page for exploits and such. Therefore, this might be something ClamWin should look at. If this works out, and ClamWin can use it, it will provide a way for Clamwin to become less dependent upon ClamAV/SourceFire.

If no one is interested in this, if you have the time, then I suggest you develop it on your own--perhaps as a plug-in/add-in that can be used by a small antivirus company looking to increase its technology/functionality. Don't get too deep into it--just cover the basics and provide a framework.

Regards,