I like autotrader.com You can set up a search and they email you updates most every day. That is how I found mine.

Flew to Arizona, bought it and drove home 2200 miles in four days - best trip ever. It is the car pictured below, had 44,000 on it and I paid $11,700 in December of 2010.

Go to Cars.com and do the same, between autotrader and cars.com, you will know about almost every Crossfire for sale - other than eBay, which CAN be an "ok" place to look.