If you've ever been out and wished you could give someone a print of something from your notebook or BlackBerry, PlanOn might have the printer for you. The PRINTSTIK is a 10.75 x 1.9 x 1-inch battery-powered thermal printer that can connect either via USB or Bluetooth; they've had it in over at TabletPCReview and, if you fit the niche, it could be your mobile salvation.
Obviously the PRINTSTIK's major plus is its portability. The Li-ion battery takes around 150 minutes to charge and at that point is good for a (rather meagre, I feel) 30 pages. Thermal paper is loaded via a special cartridge, with PlanOn quoting three pages in three minutes.
"[The] Printstik does a fairly good job printing; there were no faded letters or smudges. It moves quickly too, it took a little under three minutes to print out two pages of directions and a small map" TabletPCReview
One odd limitation is the fact that smartphone support is currently limited to the BlackBerry; PlanOn say they're working to get other devices working, but there's no timescale apart from "in the near future". It's also expensive: $299.99 for the PRINTSTIK printer itself, and $24.99 for a pack of three paper cartridges (each containing 20 sheets).