If you own legitimate copies of the games, it's painfully simple to play them from a hard drive.

Buy an network adapter. Put a hard drive of any size below 128 GB into the PS2. Buy a disc called HD Loader or HD Advance. The disc will let you store, and then play games from your hard drive. Regardless of what anyone tells you, the two programs are identical aside from any patches applied. The original versions of the discs play about 90% of the PS2 catalog. After a few patches availible on the net they were able to get slightly better compatability. You can only use the patches if you have a mod chip.

You only need a chip if you want to use burned discs to store on your hard drive or if you want to patch HD Loader.