[mh-]

Good luck getting money onto Bitcoin (for Americans) without using¹ a payment network controlled by Visa (Visanet) or the Fed (Fedline, Fedwire).

and no, sketchy in-person meetups to trade for cash don't count.

¹ directly or via an intermediary

[trevelyan]

Bitstamp is pretty good. The only problem is that the cost of an international wire is a significant part of the purchase price unless you are converting at least 1000 USD.

[obtino]

As far as I'm aware, companies don't offer direct convertibility of funds from a credit card to bit-coins.