Still on Dialup, try PhoneTray

PhoneTray Dialup will notify you when someone is calling while you are online. You can choose to take the call or ignore the call. With PhoneTray you can put internet on hold and answer incoming calls without disconnecting from the internet.

Plus, you get full-featured Caller ID software that shows and speaks callers name and number, logs all your incoming calls, blocks unwanted calls and zaps telemarketers.

Link:
http://www.phonetray.com/