What is the status on webminers? Are there any ongoing projects trying to develop a widely accessible WebCL-powered mining software? I've heard of two in the past, but their websites don't seem to be working any more.
While not directly a WebCL miner there is a miner which uses OpenCL via  Java Webstart so is accessible to any internet user with Java installed and apropriate hardware.

http://www.BitMinter.com

The site is both a pool and a custom java miner. 
The pool can be used with other miners however the BitMinter miner works only with the BitMinter pool.