Based on AnthonyUrso script with lot's of changes: Correct color solution, rubber chat window, Cyrillic! works fine, double languages interface. Please find other issue: i am support this module, but author - not.

Скрипт, основанный на разработке AnthonyUrso OneOnOne Чат. По отношению к базовому в текущей версии скрипта есть ряд улучшений: Корректно работает цветовое разделение говорящих, корректно поддерживается кирилица, обладает двуязычнм интерфейсом. И самое главное:судя по всему автор перестал поддерживать свою разработку, а я свою поддерживать буду.

Please found description of this product, published at home site 

OneOnOne Chat is a friend to friend private chat system like the one used on other social networking sites like Facebook. The module features a floating bottom toolbar that displays friends online that are available to chat. OneOnOne Chat is AJAX powered and has been tested on both IE and Firefox. OneOnOne Chat was developed because there is no other person to person chat system for Joomla. All other components and modules are group chats or visitor/webmaster chats which does not work in a social networking environment.

Features:

• FREE upgrades for life.
• Now with smileys!!!!!
• Cryllic Letter Support
• Completely programmed in PHP and AJAX for fast performance.
• Community Builder Jom Social or NONE
• 1.5 Native Compatibility.
• Multiple Chats.
• Tested In both IE and Firefox.
• Runs independent of Mootools and other JavaScript libraries for better compatibility.
• Displays fixed bottom toolbar like Facebook.

Alert sounds.