John Gallant and Holly Bergevin tell how to prepare sites for the release of IE 7 in Preparing For IE7 – Part One. If you’ve been putting off coming to grips with conditional comments, now is the time to give it your attention.
A second valuable article is Zoe Gillenwater’s Introduction to CSS Table-Related Display Values. This article is the first of two on CSS layouts that emulate the behavior of table layouts, so keep an eye peeled for the second one as well.
Both articles are free.