I bought my slightly used 2008 xb from my local Toyota dealer about a year ago. It was origanilly sold at  the same dealer and had a couple of services performed there. It had 12,000 miles on it when I purchased it. The last 12 months i only put 3500 miles on it. It now has 15,500 miles.  I scheduled an appointment for service next week.   Besides obviously an oil change what other service should be done after only 3500 miles?  I really dont what to get anything done thats not needed. Thanks  for any advice.

http://www.scion.com/#maintenance_main
They do a couple more things than change the oil and rotate the tires. The link above will give you the maintenance schedule for your XB. Ask the dealership what they charge first. My opinion is that it's not worth more than $70. If the dealership charges more than that, I'd find a local mechanic or another dealership.

Got this right from the manual: (thanks for the link, BTW)

Other than oil changes at every 3k or 5k, tire rotation (every other oil changes), there is really nothing you have to do except change your air filter. It also depends where you live, it is recommended to change it every 15k.