(Gussie, I just sent this to "Vlad" at the LLNL blog, but since you have broader distribution, I'm forwarding to you as well for your consideration to post.)
Below is a link to a spreadsheet at a personal website that several of us at Los Alamos found very useful during the transition. I checked with the author if it was okay to post again, and his only comment is "standard disclaimers apply." You LLNL folks should adjust the dates for your October 1, 2007 transition, but if you fuzz your eyes, the spreadsheet is useful in its current form, where the transition date was June 1, 2006 for us. The important thing is to not get lost in the precise details, but rather see the big picture over the next many decades of life.
Load your basic information in the left hand corner of the spreadsheet. What we found useful was the ability to project what "negative amounts" to TCP1 does vs. saving your own money in 401(k) via TCP2.