1. Virtual Keyboard
Attaches a virtual keyboard to every input box (text, password and textarea) of the current web page. The bookmarklet can be customized, see the author's web site.
2. Google Transliteration
Google Transliteration offers an option for converting Latin characters to the characters used in language of your choice (e.g. Russian). This lets you type words in your language phonetically in English script and then have them appear in the language script. Use Google Transliteration bookmarklets for typing other scripts on any web site.
3. Bing Universal Text Input
Bing delivers a similar solution with its Universal Text Input tool (see "install Bookmarklet").