[CTPP] newbie question- county to county great, how 'bout zip to zip or tract to tract?

Hi- I searched the archives to see if this question had been asked before, but didn't find anything. The census provides county to county worker flow files: http://www.census.gov/population/www/cen2000/commuting.html Great stuff. But I am interested in going to the next level and finding out counts for the number of people commuting from zip code to zip code, or census tract to census tract. And more specifically, what times the leave, how they get to work (ride alone, carpool, mass transit, etc.) Couple of questions: 1. Are there files or tables of this data that Census or someone else has made available? 2. If so, please provide url or other means of getting data. 3. If no to 1, does Census make the raw data available (PUMS?) so I could do my own analysis? 4. If so, where can I get/download/purchase the data? It would seem to me that at some point Census would not want to offer this information for privacy and other reasons - too detailed, etc. But I would be very happy with counts of people going from zip code to zip code. Any help for this CTPP newbie would be appreciated. I'd be happy to receive answers directly and summarize answers to the list in a later post, if that's appropriate behavior for this list. Thanks, Michael Nolan michaelthomasnolan(a)yahoo.com --------------------------------- Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway - Enter today