VoIP Gateway question for newbie?

Hi, I am new in VoIP so i`m interested in how should i do the following:

I want to transfer a call from a simple telephone (with pulse dialing) to VoIP phone.I heard somewhere that i can do it with a simple modem, but i don`t remember where i read it.

What kind of equipement do I need for this, it is for personal usage.
Thanks in advance.