Which programs will allow me to use my points for car rental? I have points in NW. Delta, USAir but cannot seem to find any on their sites.
Can I do it with another airline via Star Aliance?
I redeemed miles that would have expired from Star Alliance's SAS: 20,000 for a weekend, 3-day rental in Europe. Not great but better than letting them go...certain airlines within star alliance have started offering awards such as upgrades across the alliance; unfortunately, SAS isn't following suit until later in 2006. Don't know about car rentals, tho. Have you searched 'car rental' on those sites?
Before you try using points (or if you find you can't use your points the way you want), try priceline...one can get some really cheap car rentals there.
I would second the suggestion to just keep the points. Most airlines only make you earn points (you may not even have to fly...just earn points SOMEHOW) only every 2-3 years to keep the account active. Eventually they can build up to the point that you can use them for something of better value.