Oakland has a bevy of runways in all directions but only one which is used by commercial airlines, 11/29. The terminals are located on the 29 end of the runway, which is the more utilized direction. The two terminals, 1 and 2, are very boring on the inside, but at least there's lots of TV's so you can spend your Sundays watching planes and football at the same time.
-San Leandro Marina Park: Take Marina Blvd. to Neptune Blvd. and turn south. You will come to the Marina Park, which will be on your right side about 1/2-mile down the road. The park sits on the shore of the Bay and provides a good view arrivals and approaches on 29. If you take Neptune northbound until the road dead-ends, there is another park on the shore which provides an even better view, but you'll have to walk uphill for some distance before you get down to the shore.
-Terminal 1, Gate 11: Takeoffs on 29, the most used runway, are distant but nicely visible from this vantage point. On days when runway 11 is used (usually only during bad weather) it's the only place to see landings.
-Terminal 1, Gate 17: Terrific view of approaches and landings on 29. You can even watch approaches at SFO at this spot.
-Terminal 2, Gate 27: From here, the southernmost windows in the terminal, you can watch final approaches to 29.
PRE-9/11 SECURITY REPORT:
-Security is not much of a concern at OAK. The outdoor spotting locations are public recreation areas which are some distance away from the field.