<<<(no line-in on an iBook).>>>
Actually, the iBook has a high-level, stereo Line-In. No mono Mic-In, pretty much the reverse of a Windows laptop.
<<>>
There is no “simply use two mics.” Two microphones is usually the place you graduate to an external mixer. There are ways to force a system to use two microphones, but they don’t lend themselves to production. Someone posted they were going to try a “Y” cable and jam the two microphones together. We didn’t think much of the idea but urged them to try it anyway. They never wrote back.
Yes, the iMic isn’t the greatest way to get a microphone into a Mac. You’re lucky you only got the hiss problem. Mine had that plus computer noise leaking into the performance. We’ve had pretty good luck with these…
http://www.superwarehouse.com/StarTech_USB_2.0_to_Audio_Adapter/ICUSBAUDIO/p/1505202
I do very good quality recordings using one of these…
http://www.microphonereviews.com/product-reviews/microphones/shure-sm58.html
…plugged into one of these…
http://www.zzounds.com/item--PEVPV6
…which will plug right into an iBook, PowerBook, MacBook.
Independent control of four microphones or combinations of microphone and high-level stereo sources like tape and guitar direct.
There is the split between pro microphones and computer microphones. Computer microphones have plugs like this (scroll down)…
http://www.kozco.com/tech/audioconnectors/audioconnectors.html
…while pro microphones have a much heavier three-pin arrangement like this…
http://www.allelectronics.com/make-a-store/item/MIKE-3M/3-PIN-IN-LINE-MALE-XLR-CONNECTOR/-/1.html
If you decide to be happy with one microphone, you don’t need to go the mixer route, you can use one of the higher quality/pro microphone USB sound devices we reviewed here…
https://forum.audacityteam.org/t/sound-card-reviews/8375/1
Koz