*Is your Intel pc having Pentium 4 processor... If so I doubt u'll be able to install any kind of Unix on it.*
Actually that is not correct. Unix is renowned for working on all types of machines, from the fastest and newest to the old 486.
I'm running FreeBSD on a PIII 866 and it runs fine. I have a friend of mine running OpenBSD on a P166.
Unix is not hampered by CPU speed, within reason of course.
chamkila, you will have no trouble dual booting no matter what system you have. Follow the link provided by minazk and follow the instructions.
Good luck.