Ravelry is awesome. As I discovered in the wee hours of the morning, it can log your yarn stash. Skeins, yardage, weight, cost. You can take a picture of your lumps of yarny goodness and upload them with your stash info. You can put yarn up for trade/sale/free!! Not only does it keep track of your yarn stash for you, but it keeps progress and photos, ratings and completion levels of your projects!
I'm assuming there's also some feature that allows you to search for patterns that use your stashed yarn. That... would be amazing.
In other news, the pattern for the "unisex" (yet to be named) hat I posted yesterday is finalized, and I still anticipate getting it posted no later than Friday. I need to take pictures, and clean up the pattern a bit yet for the sake of clarity.