Larry, for the technical forums the answer is 'yes' -- once I take the site-level password block off.
For other forums like this usage Q&A section, and the "penalty free zone" for folks off-topic conversations -- no, the search engine bots are blocked from those.
I believe Yahoo disallows Google from indexing their forums more out of distaste for Google rather than any benevolence toward their members.
Once we reach critical mass I will also be installing a custom search engine based on Google's technology, for this site -- this will become the reincaration of the beloved (?) yellow box...