I am amazed at the amount of open source software for the Windows CE & Windows Mobile!  Of course,  Windows CE itself is shared source and that may change depending on the recently announced submission of Microsoft’s licenses to the OSI.    Here is what I have found over the past few years:

581 Source forge projects (http://sourceforge.net/softwaremap/trove_list.php?form_cat=222)

119 Search User samples on GotDotNet.com – Get ‘em quick before they disappear

(http://www.gotdotnet.com/Community/UserSamples/Default.aspx?ProductDropDownList=Windows%20CE.NET&SortDirection=Desc&SortColumnName=CreationDate)

Codeplex

Codeplex is fairly new from Microsoft to host Open Source apps.  The site is still in development and it is hard to tell how many projects there really are but here are some:

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=mobile

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=Compact%20Framework

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=smartphone

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=smartphone%20software%20

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=smartphone%20sync

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=Pocket%20PC%20Phone

http://www.codeplex.com/Project/ProjectDirectory.aspx?TagName=PocketPC
Including this interesting project:

http://www.windowsfordevices.com/news/NS8787111761.html