If you frequently take the LRT/MRT lines in the Metro, you may want to join the ongoing open beta testing of the MRTtrackr app.
I actually first heard of this app on Twitter (where else?) when a friend posted a blog link. I eventually went to MRTtrackr's website, added it on Twitter (@MRTtrackr) and applied to join the open beta.
MRTtrackr, developed by Ryan Escarez, covers the following mass rapid transit lines in the Philippines:
LRT-1 or Yellow line - runs between Roosevelt Station and Baclaran Station
LRT-2 or Purple line - runs between Recto Station and Santolan Station
MRT-3 or Blue line - runs between North Avenue Station and Taft Avenue Station