Muckyouraces:
You are right, computers cannot generate secure random numbers. For that reason most poker sites do not use computers to generate their random numbers. Random numbers are generated by hardware components that use quantum processes to generate true unpredictable random numbers.
http://www.pokerstars.com/security.html
this page provides details on the shuffle used by pokerstars.com, other sites use simmilar shuffleing processes.
Sepp