Upgrading from 2.6 to 3.0

Our team is upgrading from Unity 2.6 to 3.0, and are trying to minimize the disruption to our team's productivity.

Can I install Unity 3.0 "alongside" 2.6, so that both are installed? (giving me a choice on which version to run each time?)

If so, that would be great, which would allow us to "test the waters" with lower risk, without forcing an immediate/wholesale upgrade for the entire team all at once.

Yes, you can. But don't forget to change the default installation directory or else old version will be overwritten.

It might be apparent to some but in case you want to import an existing 2.X project make a copy of your project folder and open that.