The capabilities of GPS-enabled cell phones widely differ. Before buying a GPS enabled cell phone, consult the manufacturer and ascertain if your phone meets your requirements like whether you would just track a particular point or if you can perform data collection with regard to a specific location. Therefore, rather than asking "Can I use my cell phone as a GPS receiver?", you should be asking questions like "What level of GPS tracking does it support?" and "Which receiver has been provided in the cell phone?"
But, when you try to compare the capabilities of a conventional GPS tracking unit like TomTom or Garmin, even the best of cell phones are no match to them. A simple Garmin Nuvi 255 can outsmart a Nokia N-96, Nokia Navigator 6110, N-95 8GB, N-97, Sony Xperia, and all the latest smartphones like Garmin Nuvifone G60.
Hence, you must never think of buying a high end cell phone as a replacement to a conventional GPS device, although GPS-enabled cell phones can definitely work as inferior alternatives for personal usage, wherein the accuracy of position and time delays in tracking aren't that important. Buying Garmin Nuvifone G60 may be a good option too.