I think the proposed press release has shaped up well. Two comments:
* I had wondered about adding - for those prejudiced against the venture - something along the following lines:
"Unlike other sites on the web which erase older versions as new information is added, Wikipedia maintains an archive, for every single article, of edits and changes and discussions, so that those who refer to Wikipedia can track precisely how the prevailing view on any point has been produced."
[But maybe not necessary/appropriate in the present context? Maybe it can be said more concisely?]
* The other issue I have wondered about is in relation to comments heard lately concerning the Wikileaks saga - whether one should clarify that there is no link between it and Wikipedia?
Again, this is perhaps not the right occasion?
All the best