Congrats on having a big lot and exploring the fact iff you can split it.
Kudos to looking into "property development".
A great site is : http://www.cupertino.org/index.aspx?page=274
Your lot would have to be a tleast 12K plus.
Residential Zoning Districts
Single Family (R1)- Detached homes on minimum lot size of 6,000 sq. ft.
Duplex (R2)- Detached homes with two units under same ownership on minimum lot size of 8,500 sq. ft.
Multi-family (R3)- Attached homes such as tri-plexes, four-plexes, townhomes, condominiums or apartments.
Residential Hillside (RHS)- Detached homes on uneven or hilly terrain.
Residential Cluster (R1C) - Small lot development.
You should be just fine. http://www.trulia.com/blog/perry_mistry/
They will give you some guide line. Ask if you need to have surveying done, soil report etc.
Also ask if the property neighbors have to approve the process.
If you are looking for local architect I can recommend a few.
You need to have the access from front lot to back or the lot can be split side by side.