Stardict is a popular open source dictionary program as well as file format for storing dictionaries. There are alternatives of StarDict, some of them better, some worse. But I never meet some WEB application to use dictionaries in StarDict format and interface through the web browser. I found this little interesting and created one...
It is written in PHP and uses MySQL as database backend, client part uses jQuery for AJAX queries. Dictionaries are indexed in admin part for quick access. By now searches through 2 mil words takes about half of the second. Interface is as simple as possible and was inspired by GoldenDict. For sample usage it contains Russian-English and English-Russian dictionary(Universal, Computer, Oil, Gas...)
Try to access it here http://a32.me/other/dict/
Comments are welcome. If I have more time and some interest to it, will release it open-source .There might be interest to use it in intranet environment.
Additional free dictionaries can be found here: