how does one find travel companions through net before setting off for a journey?

web sites
i would love to travel with some one on cost sharing basis, interest arts and culture

Try an ad in an personal ads site. You can try at a few travel sites and go from there.....

http://www.lonelyplanet.com/
http://www.travelpost.com/
http://www.travelblog.org/

good answer. i was about to suggest the same pages.
also try www.virtualtourist.com
good luck :)