Fun math podcasts: Math-Life Balance, Místo problémů (in Czech).
Some of my favourite math blogs: This Week's Finds, The n-Category Café, Annoying Precision, Terry Tao's blog, neverendingbooks, totallydisconnected.
LaTeX-related: The best diagram editor ever is quiver, this online tikz editor is also not bad. Detexify will recognize a TeX code for any handwritten symbol!