Alright so I'm new to this, I recently came accross this site which details about receiving and making extremely cheap calls for just 35ish a year with skypeout and skypeln and boost mobile prepaid services
http://news.cnet.com/surveillance-st...nternet+tablet
He obviously uses the n800 for the tutorial, but I also read other threads here that said the n900 is not really a phone either, so I was thinking, if i buy it, will it ask me to insert a sim card before i use it like other phones like the iphone since the 900 uses sim cards?
or can i use it just like the n800 or n810 for just wifi and other apps?

You should be able to use your phone without a sim card as well.

I don't quite understand what you are saying chainreaction?
I thought the n900 uses sim cards, thus with no sim = no service for phone calls

You can use the N900 for everything non-GSM related without a SIM. Anything requiring the network can use WIFI.