Can you suggest me what different boards should I purchase if I need:1. to collect data from gas sensors2. and transmit/log data on my website using internet.
An Arduino, an ethernet shield (spend the few extra $ and get the wiznet one), and the gas sensors.
Check out the Nanode and Nanode RF: http://ichilton.github.com/nanode/, http://nanode.eu/
Did you mean this board?
Don't you suggest should I go for a breadboard or anything better (pre designed with sockets) since I will be installing more than 1 gas sensor?
Is it possible to send data on a website using GPRS module?