As promised, Mafia Wars rolled out the free property upgrade this weekend, so that means you have about, oh, 24 hours or so to claim this freebie. You can use this one timeon any propertythat is upgradeable and it will upgrade the property one level. Some players seem to think this is a rip-off, but I'll take any help I can get.
When you upgrade, you'll obviously want to choose to upgrade whichever property will give you the biggest payout. I chose to upgrade my Las Vegas casino restaurant because that upgrade would pay the most of my existing Sin City buildings. Though another sound choice would be to use this on the Chop Shop and Weapons Shop in New York.
Another note: When you upgrade the property, your existing building materials will stay put. So if you had, say, 2/6 Steel Girders before you upgraded your restaurant, you will still have 2/6 Steel Girders after the upgrade as well.