I know a cool website that has almost every single instruction for all the cartridges that can be refilled , so u can look up to see if your cartridge is compatible with a refill =] i believe the website was called inkreloaded.com
The best ink I have ever used (looks the same as the original canon ink) was from a company called inkreloaded. I bought ink for my Canon Pixma iP4200 and it arrived very quickly and the prices are cheap for such an amazing quality ink refill kit. In fact, im about to order another few kits for...
I think the best ink refill kits for mostly all the printers is INK from inkreloaded.com i bought my kit from them and it is probably the easiest to use in my opinion =]