Glympse is good. Will show the last place it had a reading. Hits the battery fairly hard.

Find my Friends is also good and is easier on the battery. Depends on your phone being in the network and being able to be interrogated. So if you were not interrogated recently, it won't get you in the vicinity.

Cyclemeter will tweet your position on a map every so often (interval user defined). Plus Cyclemeter gives you all the features of a bike computer and exercise log plus more.

J.