I've posted my D5100 review and the links for my Complete Guide to the D5100. The review is available immediately (duh) while the book will have first shipment three weeks from today (there's a chance it will be two weeks).
Short take on the review: the D5100 is a very competent camera. The changes to the swivel LCD (position and resolution) are highly welcome. Once again Nikon has pushed the feature specs up a bit from the camera it replaces. Image quality is essentially identical to a D7000 set to 14-bit Compressed NEF (no lossless option). Video finally supports 1080P/30, but this is a mid-range consumer camera so there's no manual exposure control for video. The D5000 was a good camera, the D5100 is clearly better. It fits very nicely between the low end D3100 and the high end D7000.
The D5100 book took a bit longer than expected because I've moved away from using Microsoft Word. This has its pluses and minuses. The big minus was all the work necessary to get what I'd originally written about the D5100 out of Word into a new word processor, and to learn the new product's nuances. The big plus is that the PDF is now better: fully cross-referenced, right down to the Index page numbers. And I'm no longer fighting Word's nasty bugs, of course ;~). Hopefully I won't be quite as slow the second time using this new workflow.