If you're looking to improve your soil or put attractive, dark mulch around your flowers and shrubs, you can get composted leaves and/or twice-ground, composted woodchips for free about 5 miles out of town at the Ecological Center in Lawrence Township. Most of Princeton's leaves go there in the fall, and if you can borrow a friend's pickup or figure out some other way of carting it back, you're in luck.
For $9/yard during weekday hours, they'll load it on your truck with their front-end loader. No cash accepted. Take a checkbook. If you want it for free, take a pitch fork or shovel along.
Location is 3701 Princeton Pike (called Mercer in Princeton), and hours this time of year are 7:30 to 2:30 M-Sat. More info are at http://www.princetonboro.org/polDoc.cfm?Doc_Id=161.
According to the man on duty, the Center gets maxed out from all the leaves coming in in the fall, and does not accept the mixture of leaves and brush the town crews collect from Princeton streets this time of year. All of that goes to a private business a mile or two further down the road.