Alameda is pretty small and flat, so getting around is relatively easy. Biking is popular. There is a pretty good bus system, a number of taxi services, and of course one can drive or walk almost anywhere. OpenStreetMap has a pretty good map of Alameda - though it can always be improved.
You drive, and you get here, or there.
For their website go to http://www.actransit.org/
For their website go to www.bart.gov/
The closest airport is Oakland International (OAK) at http://www.flyoakland.com/