Potential Solution to Wireless Reliability Issues
Finally I fixed it by doing something very simple. I went in and changed the Channel setting in my wireless router from the default setting channel 12 to channel 3. Its likely that the MPB wireless card is very sensitive and is easily interferred with other electronic devices in your house. For some reason, Channels 3 and 4 work much better.
If you have an airport base station, go into your Airport Utility Program and change your router's setting there. I have not had one single dropped session yet and I also get much faster internet (note you can confirm this by doing a bandwidth check both before and after you change channels)
Good luck!
MBP Intel Duo, Mac OS X (10.4.8)