You can find a nice home in either Millbrae or San Bruno and both are less than 30 minutes from the City and the weather is good, and both cities have Bart for transit. You might be able to stretch it to Burlingame and San Mateo as well.
Your best source to find a rental is Craig's list, or find an agent who works with tenants or property management companies. You can also contact http://www.Faytherentalqueen.com Femarie@aol.com 650-455-6072.
Welcome to S.F.
Will you be able to make a trip or two to SF to check out the area before you actually? That would be a great first start so you can begin to form a picture of the various areas around SF. Berkeley is close to SF and has the BART system. Daly City, although foggy, also has access to the BART system and is less expensive that SF proper.
Feel free to call or email if you have any questions.
Rich Bennett, Realtor
Zephyr Real Estate
David is correct. Anywhere in the city would be within 30 minutes from downtown. I would look in the Marina, Cow Hollow, Lake, Inner Richmond, Laurel heights and Noe Valley for starters.
You may also look in Marin County (just north of the Golden Gate Bridge) in Sausalito and Mill Valley (also within 30 minutes).
In addition to CraigsList and Trulia's rentals, also try Zillow's rental links. Here are SF and Marin Search links:
Feel free to contact me directly with any questions.
Paragon Real Estate Group
CA DRE 01844627