Maximum PC

I have an Apple powerbook TI 667mHz, 512 MB, 30GB, OS 10.2, CD-RW drive, with all original software, accessories and packaging. It is about 2 years old, very good condition. No dead pixels, good battery. Minor cracking of some of the paint around case edges (as Ti's are known to do). I bought this laptop for school, but wound up using it very little. I have graduated and would rather have a nice PC desktop now. A few friends and family members have expressed interest in buying it, but I honestly don't know what it is worth. Any ideas or suggestions where to find this kind of info? thanks.

$800