The official N-Gage blog has confirmed that the Next Gen Platform now won't go live until December. It's also hinted that more games may be added to the launch lineup before the launch.
On the face of it this sounds like they're missing the Xmas season, but that's not actually the case.
The compatible phones announced so far (the N73, N81, N81 8GB, N93, N93i, N95 and N95 8GB) have already sold tens of millions in total, and they're already available in the shops for anyone who wants to buy them as an Xmas present.
As for the games, they're all sold as cheap (6 to 10 euros) downloads so they wouldn't have been bought as presents anyway.