6 months/7500 miles, no reason to succumb to dealership's coercion for shorter interval.
5W-30 recommended, 10W-30 OK if temperature does not go below 0 degrees F (-18 degrees C). 5W-20 not OK. Synthetic oil better.
Owner oil and filter changes, see these Yahoo! discussion group toyota-prius messages. Joe does his own oil and filter changes in #20251. Bill Faust enjoys rotating the wheels too in #20259.
The wheel alignment of the Prius should be carefully checked and adjusted. People have found that the best setting is 0.10 degrees total toe-in (0.05 degrees on each side). This is within the range recommended by Toyota, but other settings in that range do not give as good results. Specify to your service technician exactly what you want and ask for a before-and-after report. Problems attributed to incorrect toe-in are abnormal tire wear and difficulty in steering at high speed on the highway. Some dealers apparently do not check wheel alignment before delivering cars to customers, so if you experience tire or steering problems, get this checked first.
Both Toyota and Bridgestone recommend a pattern of rear-left to front-right, rear-right to front-left, front-left to rear-left and front-right to rear-right. That is, at each rotation, front and rear wheels change places, rear wheels go to the opposite side of the car on the front and front wheels stay on the same side at the rear. See page 213 in the (2001) Owner's Manual.
Some people think that tires should always stay on the same side of the car so that they spin in the same direction throughout their life. Some people think that front-wheel drive cars should not be subjected to tire rotation at all.