Pula has its own international airport with direct services from many European cities including Amsterdam, Dublin, Edinburgh, London, Manchester and Zurich. Ryanair operates direct flights from Dublin and London three times a week. Many flights to Pula are charter rather than scheduled, while other flights are seasonal (summer only).
Hitchhiking from Zagreb works very well. In Zagreb start from the petrol station after the "Billa" supermarket on the southside of the Sava river. In Rijeka ask people to drop you off at the little SOS stop after a pretty sharp right bend of the motor way around Rijeka.
For local transport the cheap taxis from CityTax (25/30 Kuna) can be a good alternative for the public buses (10 Kuna per person).
If you want to take a small backpack with you on an AUTOTRANS bus, first ask the driver if this is OK before buying the ticket. Otherwise you might be refused entry on the bus and your ticket will not be refunded, even if you have bought it off the driver just 2 minutes earlier. See http://croatia.indymedia.org/news/2004/07/363.php for details. (The Brioni company seems OK - onboard small backpacks are allowed, but you have to insist.)
The Arena, the 6th largest surviving Roman amphitheatre. Towering over the nearby buildings this huge structure was barely saved from destruction several times during its life, mostly by various Venetians with plans to take to to Venice stone by stone as demonstration of the might of the Venetian empire. Many stones were taken to build houses and other structures around Pula, but fortunately this practice was stopped before the whole structure was destroyed. Entry gives you access to wander the inside of the Colosseum and visit the caverns beneath. The audiotour is very worthwhile.
The Forum is the main square in the center of the city. The square is built on the place of tha ancient Roman forum. On the square there is city hall that was built in 10th century and the Temple of August, from the first century.
Restaurant Galeb. You want find this one in any tourist guide, but everyone in the city knows the place: they serve best "chevapchichi" (minced meat, 2in long, 1/2in wide) in the city.
Tourist information can provide you with a list of accommodation in Pula, although they will not make reservations for you.
Hotel Riviera (1-star). Fabulous hotel built in 1907 for the high-ranking officers in the Austro-Hungarian army. Never properly refurbished since then it is now showing its age, but structurally it is impressive and looks oh-so-grand from the outside. There aren't many places you can stay at these prices where your ceiling is so far away from your floor. The rooms are currently decked out with 1960s/70s fittings (orange bedcovers, brown wooden panelling, lime green phone), with the sparseness showing the lack of funds for upkeep. Having said all that, it's clean, tidy, and comfortable. No doubt within a few years someone will make the investment to bring it back to its former glory, and prices will rise to match.
Youth hostel and youth camp. Not so nice looking place, but it is situated some ten meters from the beach, so you can almost jump directly from your bedroom right to the sea.