One of the biggest gripes I get about implementing Web 2.0 in an organisation (not just museums) is the time it takes to do Web 2.0. I have already answered that question on the Project AMEP blog post (i.e. 12 minutes and week + 2 large glasses of red wine!), but another idea I'm toying with is the notion of write once, publish many times.
I have attached a model that Bliss and I developed after working on our Project Evil audience research and be interested in feedback and comments. We're writing this up further for the next edition of the Exhibitionist.
The hard part is the organisational change bit I think - that takes time and effort but is achievable. At the Australian Museum I feel we're on track for that and will post something mid-December after we've had a series of workshops to move all of this along in a more strategic way.