Good Workaround (Rename Favorites in Google Maps), But
This is great to know, as I have been remiss to upgrade my version 3 Google Maps to version 4-whatever solely for this reason.
At the same time, while it's great to see this workaround, two things (a) I don't see this working if you are trying to save your current detected "My Location" as a favorite (which I do quite often actually) and (b) besides that, why wouldn't renaming favorites be a standard feature to start with? To me it is absolutely stunning--I don't think that's too strong of a word--that you can't straight-up rename favorites. Waiting until you get home & doing it on your PC makes no sense--previous versions let you rename in the phone, so should version 4-whatever. Period.