You can trawl through the forum and there is a lot of info out there if you search for it.
There wern't really any facelifts as such for the IS.
1999-late 2000 - S,SE,Sport - CD-CHANGER at bottom only drivers seat electric (if fitted).
late 2000 - revised CD-Changer now with CD at the top, both front seats electric (if fitted).
late 2001 - CD Sat Nav now DVD and controls for Nav more integrated in console.
around 2002 - slight changes made to interior trim and poss rear light integrated into rear spoiler on the sport.
2002/3 ish 50 bright yellow IS200s came in (think they were sports)
2004 the LE - HID lamps, full leather and another colour but basically SE spec.
later models came with Nav standard
All this is off top of my head and dates are prob a lil general. but im sure more of the guys (and girls) will add.