I have at&t viop lines including soft phones, is there a way I can configure the call vantage softphone line into my asterisk box, do you have examples of how to do that, what ip addres to use, etc.
Did they give you the SIP information ? If they did then you can simply put it in to sip.conf. If they did not (which is probably the case) than there is nothing much that you can do.
They did not give sip information, but they did give me a linksys voip router that i may be able to configure and get a phone line plugged into?
If they give you just a box then you will need to connect it to asterisk like you would connect a regular POTS line. If you want to maximize the capabilities of VOIP on asterisk I would recommend that you get an account with a company that gives you the SIP information. You current carrier may. If not have a look at:
teliax.com
flatplanetphone.com