This is starting to become an IE bug database, isn’t it? Today’s latest Microsoft “quirk” is the appearance of the so-called “double-margin” bug (details on Big John‘s “Bughouse” page). The basic idea is that items with a margin: set to any value that then also have a float: property set to left, instantly gain a margin that is double their original size.
The only obvious way around it to create an IE-specific rule that applies a margin that’s half the size you want it to be – which will then double up to be the size that it was intended once the float: property is applied.
(For a method of creating such a rule, see my earlier post that references the star html bug. Unfortunately the bug affects IE6 as well, so the rather more elegant mid-pass filter won’t apply here.)