Currently, T-shirts are available via Spreadshirt. Proceeds from the shop benefit the PyLadies organization and go toward things like nonprofit corporation setup, helping new local groups, servers, etc.
Sometimes we also create limited runs of T-shirts, stickers, etc. Check the blog or ask around in IRC #pyladies if you’re interested in seeing what we have.
If you’d like to create merchandise for your own local group, you can create a shop on Spreadshirt, Zazzle, or any other print-on-demand site and have the proceeds go toward your local group.
Or you can have a local print shop print a small run.