There are many pages where you can find information regarding GPS receivers, software, Geocaching etc. One of my favorites are: http://forums.groundspeak.com/
http://www.gpsinformation.net?
There you will find answers on most, if not all your questions.
PS
Do not visit this webpage if you do not have enough time or your wife is waiting with dinner. You probably can spend hours without noticing it and get into troubles. 😉