In Ubuntu, what is equivalent to kppp used in Kubuntu?
Kppp gives me a graphical interface, fill in the blanks to make it work.
Your ISP probably has a settings page that provides UID, PWD, phone #. With that info, all else can be found within Linuxquestions forums. Hard part is likely finding your modem on USB port. How to for that is also here.
One caution, don't worry about installing initialization strings and chat scripts until all else fails. So far, my cellular modems (air cards) work better without initializations or scripts.
ppp & wvdail are two ways to do it.