I have a PAL gameboy colour and I'm thinking of buying Legend of Zelda: Oracle of Ages off of EBay, the item on ebay is NTSC will it work with my GBC?
Generally not. PAL is the Region 2 version (Europe), while NTSC is the Region 1 version (US, Canada). I know when it comes to consoles, it will not work, but I believe that their weren't different regions for the old game boy games. But if it is listed that way, and you have a PAL, it is safe to assume it will not work.
If I remember correctly Gameboy Colours are not region coded...
PAL and NTSC apply to TELEVISIONS.
Consoles have to be made differently for the different frame-rates and screen resolution, but portable systems aren't different at all.