As part of ReadWriteWeb's Real-Time Summit they have put together a list of the top 50 companies that are helping to bring real-time to real life.  The list contains companies frm twitter to google and bit.ly to tr.im allowing you to check out some great sources of real-time development.

I thought I was kinda weird that friendfeed (facebook) was off the list since it plays a huge part in the whole real-time web arena. 

[Top 50 Real-Time Web Companies]