We did it last year.. it is VERY easy to do. Is it worth it?... another debate entirely

We got the tram from the centre of San Diego to San Ysisdro and got off at the border. You then simply walk into Mexico through a one way revolving gate similar to those in football grounds,with no checks whatsoever.
Tijuana is a smelly, dirty tourist trap IMHO, but we had been warned about this and knew what to expect. We wandered round for a while, went to the Avenue of the Revolution and had a brief look round the shops and then walked back.
There was about a 10 minute queue to get back into the US, we just flashed our passports, assured the border guards that we hadn't bought anything in Mexico - so he just pointed us in the direction of the trolley stop, and we got straight on and back to San Diego.
I am glad we did it, but it wasn't the cultural experience it is sometimes billed as. [8D]
Nick