The N900 is advertised as a mobile computer, and as a mobile computer it should be able to do a simple task like printing. So this brainstorm is for us to actually think about how we could implement it on Maemo 5.
The brainstorm thread can be located here: http://talk.maemo.org/showthread.php?t=37739&highlight=Printing
There's also a bug about this: https://bugs.maemo.org/show_bug.cgi?id=3099