leite, muito simples, posso dar um exemplo de um mod para o Wordpress.
O plugin chama-se
IM OnlineA neat little Wordpress plugin to show your current online status on your blog, with Widget support for those that use them. The plugin is powered via onlinestatus.org and supports most IM services including AOL, MSN, Yahoo!, Jabber (inc. Google Talk), Skype and ICQ. Different servers and icon-sets are available so it should be possible to find something to match your own blog.
You can show as many or as few IM network icons as you like and all options are configurable through the control panel. The onlinestatus.org servers do most of the hard work here & are worth as visit if you’re looking for a status indicator for a non-Wordpress site.
Please note that in the latest release, account options for IM Online are now always shown under Options >> IM Online, rather than through the Widget options.
...quem não perceber inglês que se queixe.
Poderão fazer o download em wordpress.org/extend/plugins/im-online/
É muito simples conseguir colocar isto num site que seja feito em php. É só aproveitar o código
