The following are some excellent links to help with module creation:

guides and tools

http://www.dotnetnuke.dk/Default.aspx?tabid=60

guide and templates
http://dnnjungle.vmasanas.net/Default.aspx?tabid=32

handcoded toolkit
http://www.hgworks.com/DesktopDefault.aspx?tabid=85

Good notes on database setup of complex modules

http://www.corderman.com/Default.aspx?tabid=95

3 article series on DNN 2.x module architecture

http://www.wwwcoder.com/main/parentid/224/site/3008/68/default.aspx

http://www.wwwcoder.com/main/parentid/224/site/3030/68/default.aspx

http://www.wwwcoder.com/main/parentid/224/site/3084/68/default.aspx

Jim Duffys excellent DevX.com article

Build 'Radioactive' Web Sites with DotNetNuke 2.0

Stan Schultes presenation to Onetug

Building DNN Private Assemblies Slide Deck

step-by-step tutorial for creating a DNN module using notepad

step-by-step tutorial for creating a DNN module using notepad