Hello, there are a number of flash paint programs that the N900 can run.

Onemotion.com/flash/sketch-paint Is quite nice and usable

sumopaint (almost a carbon copy of photoshop) runs a little slowly (it has layers, history pallete etc). Hopefully flash 10 (or an overclock utility) will improve them.

I typed in flash paint in google, there where quite a few more, but it was late. These were the two I tested.

Of course they both miss out on pressure sensitivity, which is something I love about 'colours' on the nintendoDS