- Information about LaTeX.
- Terry Tao has a nice page On Writing full of useful advice on mathematical writing (and reading). John M. Lee has some good tips regarding writing proofs.
- The NSF’s list of REU sites.
- The AMS has a helpful page of resources for undergraduates.
- The MAA has a resource page for undergraduates and also provides some funding opportunities for undergraduates.
- SIAM has a resource page for students as well.
- Pathways to Science is an interesting resource.