Here's a good starting point:

http://www.pollinator.org/PDFs/MontanaBeeGuide-Final.pdf

It would look like a honeybee https://www.google.com/search?q=honey+bee&safe=off&espv=2&bi...

A lot of what you're seeing are probably wasps (the yellow jacket being one variety).

tptacek has a very efficient guide to bees posted. Another nice national one that is very comprehensive is the USDA's guide at http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb530646... . Scroll to page 17 or so to start looking at illustrations of particular bees if you don't want to read about their habits. But the best for CA is the Berkeley Bee Lab's page on native bees at http://www.helpabee.org/common-bee-groups-of-ca.html

There was a great art & education & science installation on native bees at the UC Botanical Garden in Berkeley a few years back (http://www.sfgate.com/homeandgarden/article/Shirley-Watts-Mo...). I know they still have a beehive, and they might have some exhibits on native bees.

The Berkeley site is neat, but it's got a picture of the european honey bee right at the top and no mention of it being non-native.

> What would a non-native honey bee in the wild look like?

It would look like a honey bee. None of them are native. Native bees are orchard mason bees.