I haven't had confirmation as to whether the 2003s come with it, but the 2001 and 2002 Prius in the US do have the free 3yr/37500mi maintenance included.adeshell said:
Look in your 200X Prius Passport to Performance Scheduled Maintenance Guide. (Make sure it says "Prius" and isn't the generic maintenance book for all Toyotas.) If you read the first few pages, it'll list off the free services. They're good at any Toyota dealer, although some aren't as familiar with servicing Prius so you'll have to remind them that your service is free.
The free services are for the regular duty cycle scheduled maintenances. Basically, it's the 7500mi/6mo services that are an oil/filter change and tire rotation. Eventually the passenger compartment AC filter and the engine air filter also get replaced free, too. So, it's your first 5 services (up to the 3yr/37500mi service).
See http://www.john1701a.com/prius/prius-maintain02.htm for the regularly scheduled maintenance guide from the 2001 Prius. The severe duty schedule is not included on this page.