Generally, I'd say that in-person networking will be your best bet, unfortunately your profile indicates you're in India, so I'm not sure I can recommend any good events/groups to you.
However, if I was in your position, here's what I would do:
Find startups you like, and follow their company, developers & CEO's on Twitter - chat with them there to get to know them and see if you can help out or if they know someone you can help. Startups know other startups so this is a good route. Here are the twitter handles for a few early-stage companies I'd recommend (ie. I've met the founders and they would probably welcome help): @giftah, @welldotca, @guestlistapp, @sprouter
Look at job postings on freelance sites that talk about "new company" or "startup" e.g. elance.com, scriptlance.com, getacoder.com - see what's interesting there.
Build a profile/portfolio: your profile on this site doesn't tell me much about you. If I were considering having you help my startup, I'd want to see links to work you've done (e.g. live sites, code samples in code.google.com, open source projects, articles you've written, etc). If you don't have this stuff up on a blog, I'd recommend you do so ASAP.
Contact people that work directly with startups, and send them your pitch and portfolio (see #3 above). I'd contact angels and small boutique VC's, as well as accelerators. So - drop a line to the folksat ycombinator.com or acceleratorcentre.com and let them know you'll help one of their startups if they want.
Consider joining and posting your request on Sprouter.com - it's a twitter-like community specifically for entrepreneurs, and the community managers there are VERY active in trying to get people connected.
Not sure this is the answer you're looking for, but I hope it helps.
