What are the typical race distances?
Sprint – Most sprint triathlons have a 400-700 yard swim, an 8-15 mile bike, and a 2-4 mile run.
Olympic – An Olympic distance triathlon consists of a 1.5k (.93 mike) swim, a 40k (24.8 mile) bike, and a 10k (6.2 mile) run.
International – An international distance triathlon is similar to an Olympic distance, but can vary a little. Maybe the swim is a little longer.
Half-Ironman – A half-iron distance triathlon consists of a 1.2 mile swim, a 56 mile bike, and a 13.1 mile run.
Ironman – A full ironman distance triathlon consists of a 2.4 mile swim, a 112 mile bike, and a 26.2 mile run.
What is a good distance / race to start out with?
This is highly personal and dependent on your level of fitness and comfort with the three sports. Many people start out with a Sprint or an Olympic distance race.
For the Sprint distances there are some great beginner series locally, such as the Blue Lake Sprint, Olympic and Tri-it (novice) races. If you'd prefer your first experience to have a pool swim rather than open water, then races such as the Beaver Freezer, Albany Triathlonand Lebanon Triathlon are good races to start with.
Don't be shy. Talk to the folks you are training with and those with a little more experience to get a feel for things.