Google talk blocked at your office, college or school don’t worry you are not alone in this as there are lot more other people like you who are being troubled as various messengers are being blocked access. But there are still lot more ways with which you can access the blocked messengers in your office and you can still keep chatting with your friends.
Firstly there are large number of online sites which allows you to access gtalk, yahoo and other messenger service online via web interface, following are the links to some of the web services.
Following are the official web messengers form AOL, Google, Microsoft and Yahoo which connects to the messenger services
Another way to access the blocked gtalk, yahoo and other messengers is by installing other alternative messengers which allows you to login to google and yahoo etc for chatting.
Here are some alternative messengers which lets you login to yahoo and google,you can download from the respective links given below