The typical asking rate per listing is in the $20's per square foot per year. The Anaheim region is going through a a boost in rates. In the last 3 months, the median rate rose $6 per sqft per year. That's a 30% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Anaheim region has less expensive rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 40 listings have been listed, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 110% of the available space in the Anaheim are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,900 sqft. Most properties in this area are approximately 2 stories. Most buildings in this region were built in 1982 and are Class B.