With the release of The Sims 3, and the flurry of activity it has created, we have instituted a regular front page update for modding news and new tools. If you are interested in more information, please click on the links below.
Delphy has released the CAS Texture Unitool that aims to let you create designs on T-Shirts and such. Keep in mind that it is still in Beta; so bookmark the link for updates. There are also new tutorials for Create a Sim artists. See: CAS Tools and Tutorials
There are two new tools available for custom pattern creation: Delphy's Pattern Packager, and The Sims 3 Workshop.
Each program is a bit different. Try both to see which one better suits your needs. There are also 4 new tutorials on pattern creation. See: Pattern Tools and Tutorials
Wes Howe is doing work with Milkshape plug-ins at Custom Sims 3. He has also written a tutorial, available at the same site. Meshing Tools and Tutorials
Feldynn has written a very useful tutorial on roofing, to create a basic roof with different slope angles, and aphexZero has a tutorial showing us how to build an aquarium pool in The Sims 3. Find them in the Build Section. It's also worth noting that many TS2 build tricks and techniques work exactly the same in TS3 (for example, building a walk-out basement).
Lots of new tools for installing sims 3 content such as Delphy's Install Monkey and Marhis' Installation tool for Mac users. Click here for more info on all the new installation tools.