I'm working on my first big PocketPC app with the .Net Compact Framework.  I've been pleasantly surprised that I really am up to speed on the topic (considering that I have my Dell Axim strapped to my side).

Some stuff you should know before starting any kind of development with the Compact Framework.

1) Go to OpenNetCF and bookmark their site they are going to have some very pertinent articles and links that you'll need
2) While you're there grab their framework which adds a number of features of the regular Framework back into the compact framework (stuff like XML Serialization, WSE2 support, and much, much more).  You really need it!

Ok, some cool stuff I'm doing in my app.  The app itself is a simple little capture data save it for later, let me search it, and then send it somewhere when I get connected to the internet.  I'm actually using the compressed (serialized) dataset described here.  I have a complete mini database for CF purposes (very cool!) and later I'll be able to push the file if I want to some big framework app and be able to use the same library.  I've even added to the original library.  I didn't like that I couldn't save.  I have some more stuff I want to do with it, but I'll definitely post it (is there any easier way to post code other than creating a GotDotNet workspace (I really don't want to continue working on it...) 

I'm also using Justin Weinberg's “Another Multiform Framework” (which is a modification of something Chris Tacke did).  I really like it!  It mainly accounts for the fact the DotNet CF doesn't do a great job creating controls as well as launching new forms can take extra work... anyway, read the article if you're interested.  BTW, I read the article on OpenNetCF... so see they are an awesome resource.