Available on EMusic, Amazon, and iTunes.
I think Fats Waller is still pretty popular right now for swing dancing--maybe due in part to Skye & Frida's ULHS routine from last year. The song they used, 24 Robbers, is available on the album "The Unique Mr. Waller," which has lots of other good dance tunes on it. I'm sure the tune is available elsewhere too--I'll let y'all dig around for it yourselves, if you haven't already.
I like Fats because his combo is good at laying back, relaxing, and then turning it on and jamming out. And of course, a lots of his songs are hilarious--take "Hey! Stop Kissin' My Sister!" for instance, or "Your Feet's Too Big." Sometimes he sings quite sentimental material, and walks a fine line--hamming it up, but still delivering a sort of earnest performance. His solo "Two Sleepy People" is a great example of this.
"That Ain't Right" actually comes from a performance in the 1943 film Stormy Weather, which features an all-star line-up of performers, including Bill "Bojangles" Robinson, Cab Calloway, Lena Horne, and the Nicholas Brothers. If you haven't seen the film, check it out. You'll be blown away. Here's a clip:
It's not just that Fats sings silly songs, it's that his timing and rhythm are so perfect and so expressive. "That Ain't Right" is a great example, a slow, jazzy blues number featuring vocalist Ada Brown. Her voice has a commanding power and a great timbre. As she sings, Fats talks back to her and kind of draws her along. He's full of one liners and jive talk, of course ("Beef to me mama, beef to me! I don't like pork no-how..."), but what's really striking is how he fits it all in to the phrasing of the song, and makes it rhythmical. The give-and-take between Ada and Fats is funny and charming. I love the climax of the song, where Fats delivers the punchline (again, with perfect timing) and then the band comes in at a faster tempo.