Hey, Richard,
There are several online sources for Mobile 2005.
First, there is a newsgroup on Microsoft's public news server (news.microsoft.com), at microsoft.public.dotnet.framework.aspnet.mobile. (and there's MSDN as well).
There's at least one category on gotdotnet.com for mobile devices. If you google on Mobile 2005, I'm sure you'll find other good resources.
Kevin