Angellist seems to be where the most frothiness is. Some good stuff there but a lot of "me too" action.
If you know what kind of startups you are looking to invest in and want to do your own due dilligence, I'd troll various startup events where people pitch. Here in SF you could go out to these 5 nights a week practically, but I know there are some in any large city.
Also identify other angels who are investing in the kind of businesses you want to and contact them, they often need others to finish a round.