The book I always recommend to get up and running in WCF quickly is Learning WCF by Michele Leroux Bustamante. She covers all the necessary topics, and in a very understandable and approachable way. This will teach you everything - basics, intermediate topics, security, transaction control and so forth - that you need to know to write high quality, useful WCF services.
Besides that book, I also really learned a lot from these two one-hour screencasts on WCF:
- DotNet Rocks TV Show #122: Miguel Castro on Extreme WCF
- DotNet Rocks TV Show #135: Keith Elder Demystifies WCF
