Forum OpenACS Q&A: Re: TCL function for capturing browser type
If you do need support for transparency and need to avoid all the CSS/PNG land-mines in IE here's two links for possible solutions:
All this hackery should soon be a thing of the past if Microsoft will ever release IE 7 (or everyone switches to Firefox).
As for support of IE version < 5.5 -- I don't think you need to worry about it. From looking at the web stats for the sites I run it appears that for the past year 95%+ of visitors using IE are at version 6. For the remaining 5% using ancient versions of IE, I suspect their browsing experience is so poor that the lack of proper PNG image support is the least of their problems.
Thanks a lot for all the advice.