Localization does pose some difficulties even though I would like to believe the exact opposite :) ... So it was nice to read a post that is pretty comprehensive and makes it look easy. hmm... my belief is strengthened ;)
brunzefb has posted this localization article on Codeproject and it is a must read for all who plan to/are creating a WPF app with the international audience in mind.
I'm a big fan of WPF, but less so of LocBAML. In my experience, once your WPF application gets a little more complex than a bunch of labels and buttons, LocBAML will produce tons of false positives in the CSV file. Also, if you're attempting to produce XBAPs you'll need to figure out how to regenerate the manifest to include all the resource dlls.
If you're looking for an alternate approach, especially for XBAP applications, I have a description of one at my blog: http://www.geektieguy.com/2006/12/12/localizing-an-xbap-application-without-using-locbaml/
(Unfortunately my site seems to be unavailable as I'm writing this. Hopefully that will be resolved when you read it, should you decide to want to look at it.)