i duno much about debian however wvdial must be aviable on debian too coz its open source..
If it is not there then download it.
wvdial configuration is very easy. as I remembered first you have to run
#wvdialconf /etc/wvdial.conf (however you must check the man pages)
This will creates a wvdial.conf in /etc , open it with your fav. text editor and there you have to uncomments the lines for your ISP dialup number, username and password.
Now its time to check it
#wvdial (remember as root)
this will dial your ISP, if everything in wvdial.conf is okay then you would be connected otherwise double check teh conf file.
Okay if this works then its easy to dial it automatically on each restart and im should sure you know how?
put the wvdial command in one of your startup script probably rc.local , however I duno what rc.local called on debian