A realtor can help you with this request -- but you're running out of time.
SELECTING THE COMPARABLE PROPERTIES
Just getting a list of homes sold prior to March 31, 2008 is not going to help you because to apply for this reassessment, you or your realtor must select properties that are comparable to yours, and within the immediate vicinity of your property.
For example, if you have a condo in downtown Oakland, you shouldn't compare your property to a house in Montclair. If your place was built in 2000, you shouldn't compare it to a Victorian.
Here's the info you should provide your realtor:
* Exact street address. If it's a condo, the exact unit number
* From there, the realtor may be able to get the square footage, number of bedrooms/bath(s), year built
* How much did you pay for it, and when
* Your realtor should also be able to pull up the current tax assessment
COMPLETING THE FORM
* Your realtor will then look for properties that sold at least 6 months before March 31, that are comparable to yours, that are in the immediate vicinity of your property (due to Oakland's density, that radius may even be just a few blocks from yours)
* And the realtor will select at least three properties that are comparable to yours
* Enter information about configuration, bedrooms/baths, when sold, and for how much
* From there...the realtor may be able to extrapolate and recommend the value of your property during this time period.
* The realtor will complete the form, sign it
* Then you sign and send to the Alameda County Tax Assessor's office
NEXT YEAR'S ASSESSMENT -
For year 2009, the new assessment won't be available until July. If you disagree, then you have the opportunity to apply for reassessment, following the same procedure as in 2008. But you can't submit your application for 2009 until after the end of July 2009.
Hope this helps.
For more information, go to http://www.acgov.org/assessor/reassessments.htm.
And here's a link to my blog about Alameda County Property Tax Reassessment Reassessment for property values in Alameda County, CA
If you don't have a realtor, and you need help right away, call/email me via my profile on Trulia.
Give me the exact street address (and unit number if applcable), year purchased and for how much. I'll do my best to get this done by tomorrow, April 10 which is the deadline to submit the 2008 reassessment application.