HTML character sheet? Are you simply looking for a template upon which to build a webpage, or are you looking for something interactive (an HTML form for example) for your campaign members to use? This would require a database or server scripting to store the character data in. I've thought about creating a web-based form, but I haven't seen any.
The best option for this I can think of is to use a decent from-based PDF character sheet. Something small (in file size) would be best. PDF's can be viewed within most web browsers with Acrobat Reader installed. I've got mine (see my signature - though the PDF is pretty hefty), and I've seen some good ones on RPGSheets.com.