calculating miles

I was wondering if anyone knows of a website that helps calculate how many miles you are running. I run around my neighborhood in brooklyn. Some blocks are normal and some are avenues and are much longer then a normal block. I want to know how far i have been running. my route is about 30 blocks but again because of the varying sizes of the blocks i have no clue how many miles I'm going.

Thanks!

http://www.mapmyrun.com/

http://www.gmap-pedometer.com/

yay thank you guys!!

I like google map. You can track your own route: maps.google.com.