[mattcrest]

I'll throw in a recommendation for PayLeap (http://www.payleap.com) as a combo gateway/merchant account.

As for the the delayed billing, something like OpenGateway (http://opengateway.net) might work. It is set up for subscription payments, but there's a way to work around it. You could essentially set up the initial payment with a 30 day free trial (although don't really call it that), then automatically bill after the trial period. And instead of then billing every 30 days like a traditional subscription, you make set it up so it only charges once (no repeat).

I recently used these two in conjunction and have had great support from both companies. PayLeap has superb phone and email support and OpenGateway has solid email/web support. Also worth mentioning, I'm not an experienced ecommerce or subscription guy, but both systems were pretty easy to work with.