The apple headset will work. Just because it has a mic in the headset doesn't mean it will work. I found that out. I have the sennheiser mm50's, they work great.
Yes you will need fring and if you have a skype account you can use that. I don't like Skype, I find the quality not that great. And cause I am in Canada I can't get a virtual number to receive calls. I set an account up with
www.callwithus.com. I got a number and voicemail, it costs about 8 bucks a month. But it's handy for me cause I use my ipod touch mainly for my work.