well if its to sponser a site?

then generally you can just bug everybody and show then your site and tell them what you hope to give to them in return of sponser (hosting fees) etc...

But be carefull what you sign! - As the sponser (persons) may want you to have pop ups all over your site, advertising in newsletters, massive banners down the left / right / on top / middle of you nice web site.

But if you become big enough without them then you soon have them offering you deals.