Hi N
1) multiple browser windows no problem just don't try and edit the same listing in two windows things may get confused.
2) any combination of FF and IE6 works for me
I and others have found FF much faster to use with Auctiva's online listing edit/creation tools than IE6, IE7 don't know. (O/S = XP)
Also the community boards and the editing are on two different sites so if the main site (listing etc) is down for maintenance this one the eve-community site seems to always be up.