I came across these really creative ideas for some unique changing tables. I love the yellow tool cart (post found here at Ohdeedoh) and I'll hopefully snatch up one of these for the nursery.
You can find these 2 Steel Service Carts from Harbor Freight Tools...here and here..for some reasonable prices (maybe even better than an actual baby changing table).
At Daddy Types, you can find another great idea for a changing table. Check out this Stainless Steel Kitchen Cart from Ikea.
Now get this...a great DIY idea when your little one no longer needs a changing table, or outgrows it. Instead of chucking it, turn it into a bar! Here are the before & after photos from Ohdeedoh.