What other marketing have you done? A mention on Techcrunch is nice if you can get it, but if that's your only marketing vector, you're not going to succeed at all.
USP of my site is you can bet on any team from any twitter client by just sending out a tweet in a particular format..
To get to normal twitter users what should I do really??
at the moment, you ask users to tweet eg "@betnext 5000 on SomeTeam - Feb 7th 2011"
Change that to "5000 on SomeTeam Feb 7th 2011 #betnext". to me a hashtag is better promotion than an @reply.
^^ why I comment on HN :)