That was the first modification I made when I got mine. In my previous vehicle I didn't even have a radio, just the iPod playing directly through amplified speakers.
I, too, had the basic OEM system, and used an FM modulator (not a transmitter - I already have an iTrip, but I live in NYC so it's even worse than normal). This is a powered unit - so you tap into power and ground - that connects inline between the antenna and head unit, and has stereo RCA jacks. It basically hijacks a specific FM frequency and you tune to that station.
It worked pretty well, much better than a transmitter. I drove cross-country with it and there were only a few times when I must have been close to a station broadcasting on that frequency where I got some interference.
I also used the Belkin Auto Kit which plugs into a 12V adapter, has a built-in amplifier, and connects to the iPod with a dock connector. It's pretty good, the charging and dock connection were what I was mostly going for. I'm not sure about the usefulness of the amp - you can sort of match the volume level with other sources, but I don't know if it's all that necessary.
One of the pieces I'm most impressed with is the mounting system from ProClip (
http://www.proclipusa.com). The mount they have for the Escape goes on the passenger side, but if you use the iPod holder with the tilt swivel mount, you can mount it on the driver's side. I got the padded one and it's such a perfect fit, super secure, great product!
I have recently installed a new head unit and new speakers. Much nicer! My new head unit has a line-in input so the FM Modulator is about to go on eBay, but . . . wait a minute . . . Tammy, with the lemon? Is that you? If so, I'll give it to you if you want it. Email or PM me your address and I'll send it off to you along with the OEM tools to pull the head unit out of the dash.