Is there any sort of protection that I can use to prevent players from using hacks or play through a third party program?

Some links that might help:

http://groups.google.com/groups?lr=&...ty&sa=N&tab=wg

http://www.onjava.com/pub/a/onjava/2...avsdotnet.html

http://www.google.com/search?lr=&ie=...ava%20security

thanks =D