when i am playing chess against my friends here we like to chat as we play but can you use a web cam on this site so you can see each other while you play ? 

There has been some discussion of this in the past, see this thread for one such example. But basically, this isn't really a feasible option on Chess.com at this time. But there is nothing stopping you from using another software that streams webcams (Yahoo! IM, for example) with other users while you play.