1. Yes, there will be the "express" and "network/redistribution" installs available for download in the final release. They will both contain the same features, though the network version (like ryan said) will allow you to slipstream cd's.
2. The built in firewall can be disabled.
3. sock, yes most new copies of XP sold in stores contain Service Pack One, it should also be listed on the side. And according to the WindowsBeta website this will also be the case with SP2 when released.
4. The current network install package is over 200mb, however by the final release it should be smaller.
5. Sockie, just so you know, Microsoft intends to scrap IE as a separate browser and only include it with windows releases
Chris