The recommended way to unclog print head is to run deep cleaning once or twice and then leave the printer for 24-48 hours and hope the wet ink will break down the dried ink in the nozzle. This is the slow safe method.
http://www.posteriza.com
Found a freeware poster maker...not quite as slick as Pro Poster but it is Vista capable so it doesn't turn off the theme like pro poster would.
1. The Canon website has the specs for all the models.
2. Hobbicolors sold on eBay is good. Also Formulabs sold here: http://www.alotofthings.com/viartshop/products.php?category_id=2
Don't do any of those things...simply leave the printer plugged in and turned on and you shouldn't have any problems with clogging.
I've gone 6 months without printing and still printed a photograph flawlessly.
I assume you guys are using good ink like Canon's or Hobbicolors.