Can I use ThinkPad as a phone?

[hhchou@cs.UMD.EDU (Hui-Hsien Chou)]

HI, I have the problem that I only have one phone plug besides my
desk. Whenever I want to talk, I plug it in the phone, but when I want to
use internet, I plug it in my ThinkPad. 

I understand that my ThinkPad has a microphone and a
speaker. Therefore, I wonder if it is possible to use my ThinkPad
directly as a phone? Is that possible?

Thanks in advance.

hh