AMR acutually recently did a mass hiring of about 50 new EMTs to make up for the EMTs lost to other companies in the change overs of Santa Clara County and the soon to be change over of Alameda county, AMR its always best to get as many apps in as possible and just wait, there are also the IFT companies which is where I know most people got their EMS starts in, Myself included in that, its a good way to get some experience on the rig in a low stress environment.
The IFT companies
AMR IFT South (Includes San Mateo, Santa Clara, Half of Alameda County, Santa Cruz)
AMR IFT East (Includes North half of Alameda, Contra Costa, and I think San Jouaquin)
AMR San Francisco (Also does 911)
Nor Cal Ambulance (Alameda County)
Royal Ambulance (Alameda, Santa Clara Counties)
Bayshore (San Mateo County)
Silicon Valley Ambulance (Santa Clara County)
Westmed (Alameda and Santa Clara Counties)
Protranport-1 (Alameda, Santa Clara and San Francisco County)
There are plenty more
911 Providers
AMR San Francisco
King American Ambulance (San Francisco County)
Rural Metro (Santa Clara County)
Paramedics Plus (Will be 911 in Alameda Starting Nov. 1st, 2011)
AMR Santa Cruz
AMR Contra Costa
Medic Ambulance (Vallejo)
Sonoma Life Support (Sonoma County)
and there are more