My favourite patterns are:

Curly Purly Soaker (Free)
Everlasting WonderSoaker (from Woolly Wonders online store - you pay and they send teh PDF)
Picky Pants (pay and they send a pdf) for longies/shorties

Great wool stores for varigated hand dyed yarn are Jolly Jumbuck and Monster Knits.

All of those should come up if you google them. Steer clear of machine washable wools as tehy tend to be treated so they lose some of their original woolly qualities. They might be supersmooth but some don't hold the lanolin as well so aren't as leakproof. The less treatment it has been through teh better. I have some pics of some of the soakers/ shorties/ longies I have made in my blog if you want to see how the patterns turn out - click the completed projects for 2007 in the sidebar as they are not all recent projects - I am just starting on the soakers for summer now as his old ones are too small. (Just about finished my first Everlasting Wondersoaker and I loved knitting it! Hope it works as well as it knits!)

My blog: Joystitch Knits and Bits