Microsoft's Mike Ormond has gone ahead and finally published a nice eBook called "Building Windows Phone Apps: A Developer's Guide", which looks to give a "puddy up" "into developing on the platform and, importantly, helps you to avoid making the same mistakes others have made".
The book was done as a collaboration between various volunteers in the community, including Colin Eberhardt, Pete Vickers, Andy Gore, Mike Hole, Gergely Orosz, Sasha Kotlyar, Dominic Betts, Will Johnson, Ben Cameron, James Bearne, Samidip Basu, Paul Marsh, Stuart Lodge and looks to be dynamic, with new chapters added over time.
"The plan was always to publish an initial set of chapters and then iterate, adding new chapters and updating / refining existing chapters as we went."
Seems like a good resource for devs out there and seeing as it is free, there's little reason to not grab it. More info can be found on Mke Ormond's blog here. Thanks, Aleksandr (Sasha) K., for the tip!