I have some reservations about using third-party widgets when there are so many exceptional, so many more robust commercial solutions available on the market, but if you're just getting started on the Web and are looking to add chat room functionality, the 99Widgets Group has launched 99Chats.com, a free flash chat room widget that might be of interest.

99Chats.com is fully customizable (colors, background and fonts to border style, size and design and even the opacity level), but webmasters and weblog owners can also create their own themes or choose one of the ready-to-use themes available.

What is unique about the solution, and what will be interesting, is that 99Chats.com allows users to extend interaction with visitors with realtime text messaging on almost any web resource as it uses pure flash code. 

99Chats.com is lightweight and takes only 65KB. It also supports tabbed private messaging with chat members, block user, and flood detection and prevention mechanism, and it works in any language. 99Widgets actually has quite a few widgets available, including those for polls, counters and others.