I'm having the same issue over the last few days. Sometimes it just says "connecting..." and then saved but never connects. Password is fine. Now as I'm typing this out it magically connected. Weird. I'm on a Linksys WRT54G running Tomato firmware.
So Walmart sells Straight Talk sims for T-Mobile? Why doesn't the Straight Talk website sell them if they provide T-Mobile service? I just bought a Nexus 4 and wanted to use T-Mobile but the only option on their site is AT&T. I am in Chicago and T-Mobile does serve the area (HSPA+ I think.)...