I've never been to war, but I imagine the experience has many similarities to making your first 48 hour film.
If you're producing, I recommend you think of it as a 41 hour film festival. You will lose time at the kick-off event, and you also have to factor in about six hours of sleep over the weekend (if you're running the whole show). I did it last month in DC and I broke it down to Friday = write/plan, Saturday = shoot/capture), Sunday = edit. Needless to say, that was not enough detail for me to finish on time. You really need to plan hour to hour.
Here are some time-saving tips from me:
1) Deliver the film on miniDV. That way output is 8 minutes -- don't waste time rendering or burning a DVD.
2) Think about total man hours. It helps to have talented people who can do multiple things, but it helps even more to have talented people focus on one job. 3 people x 41 hours = 123 man hours, whereas 20 people x 41 hours = 820 man hours. There are of course advantages to guerilla-style crews, but a key place to save time is to have an editor or someone that can capture tapes while you're shooting.
I went to the "Best Of 2005" screening last night for the DC entrants. They showed about a dozen films and I'd say 5 were excellent, 3 were good, and 4 were just plain bad. Strangely enough, 3 of the films were *about* making a film for the 48 Hour Film festival--regardless of the assigned genre. I think there were 4-5 24P DVX100 films and they looked much better than the 60i entries. MUCH better. The DVX footage looks great projected using state of the art digital projection, but the only gotcha was with blown out highlights. Blown out backgrounds are not pretty all and if you can avoid doing this you could easily mistake good footage for 16mm work.
I did this last year too. We took the Audience, Acting, and Score awards. I just paid my fee for this year. We were the last team to make it in (San Diego). It's an awesome and fun experience. By the way, if anyone is in SD on the weekend of July 15th drop me a line and come help out if you want.