DNNCreative hasn't really specialized in module development. Rather, our focus and tutorials are on using and configuring DotNetNuke. But there have been some excursions into module development.
Historically, Michael Washington's adefwebserver.com site has included some great material on module developement. I recommend it. Michaael and Ian Lackey also have a recent book that include the module development topic.
I highly recommend Mitchel Sellers' book on DotNetNuke module development.
Recently, Chris Hammond at DotNetNuke has been creating a series of video tutorials on module development. Take a look at
http://www.dotnetnuke.com/Resources...pment.aspx for links to what is there. Also, Chris' blog has discussions and links to other quite helpful material on module development.