Mybus.org is a great program that allows you to get real time bus information for major intersections. To improve the user interface I created a google maps mashup that overlays this data onto a map. All you have to do is zoom in on where you are, click on closest marker that your bus stops at, and you'll get real time arrival information.
Once your away from your computer you can text the bus stop number with an @ symbol before it to email@example.com (I know it looks like an e-mail address but it works for all phone that can text message) and it will reply with the real time arrival times of buses coming to that stop.
or if I just want the route 43 information
or if you forgot the stop number or want another stop number that the 43 stops at text