Pretty much almost all the major mileage earning credit offer the no-fee version of the fee-based mileage earning card, but at a ratio of earning one mile for every $2 rather than one.

Examples that I am sure offer the no-fee version include: BankOne's United Mileage Plus card and British Airways visa, US Bank's WP visa, Chase's One Pass credit card, and Amex Delta Skymiles card. I am sure there are others, but these are the ones that I have personal experience with.

Also, don't forget about the MBNA Amtrak Rewards card that offer a one-to-one redemption value on UA Mileage Plus miles and CO Onepass miles with no annual fee. IMO, this is probably the best mileage earning credit card that does not charge an annual fee. Further, you have a choice between two airlines from which to choose.