Here is a cool program called Game Cloner. It can't copy Xbox, only PS2, but since that's what you want I guess you're in luck. It costs about $35 USD, but I'm sure you could download it on P2P.
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Some of the best programs to use are DVD Decrypter and anyDVD. It's good that you have a modded system, because you usually need an alternative boot method for copied games.
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You can also use hdadvance to copy your games. Converts DVD-9 games to HDD.
Overview for the product:
HDAdvance allows you to convert your PS2 games to HDD and run directly from the HDD connected to your console (PS2 Network adapter and compatible hard disk drive required). The HDAdvance package includes a CD and a DVD: The CD version embedded with the largest TOC. It can convert all CD games. The DVD version also embedded with the largest TOC. It can convert all DVD games.
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Here is a great thread about copying games as well.
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Hope all that helped you a little bit.
