USB is fine, if you have a USB enabled microphone preamp/interface, or a USB mic, which is a mic with a built in preamp and USB interface. There are only a handful of USB mics made, and they pretty well only come in 2 categories- pretty cheap, and really good and the price of a good used car. It sounds like you think a regular mic can be plugged into a USB port, but it can't. There are plenty of USB enabled preamps and interfaces, and because you don't need a bunch of channels, you have lots of options. For instance:
For dirt cheap- no phantom power, which means you can't use condenser mics, but will work fine with your Sennheiser, and comes with Cubase software:
http://www.8thstreet.com/product.asp?ProductCode=41562&category=Audio_Interfaces
Similar unit, no phantom power, but with guitar/instrument input and some effects. No included software, but will work with Audacity or whatever:
http://www.8thstreet.com/product.asp?ProductCode=27765&category=Audio_Interfaces
A little more money. Very much like the above, but with a somewhat better preamp and phantom power. Who knows? You may wind up getting a condenser mic, and phantom power will become a necessity:
http://www.8thstreet.com/product.asp?ProductCode=12031&category=Audio_Interfaces
Here's an interesting micro-unit with phantom power. Good for mobile use with a laptop:
http://www.8thstreet.com/product.asp?ProductCode=45027&category=Audio_Interfaces
Another perfectly good unit by Tascam w/ MIDI capability, phantom power, Cubase software included:
http://www.8thstreet.com/product.asp?ProductCode=41708&category=Audio_Interfaces
That should give you the idea. Whether you are going into a dedicated soundcard, such as:
http://www.8thstreet.com/product.asp?ProductCode=7587&Category=Audio_Interfaces
or one of the USB interfaces, somewhere in the system there has to be a preamplifier. The separate preamp and a dedicated soundcard is a more expensive route, and more versatile for a variety of recording, but for your limited needs, a USB interface may be the best option, bang for buck. And yes, there are USB mics- example:
http://www.8thstreet.com/product.asp?ProductCode=43670&Category=Microphones
but if you already own that Sennheiser, you are likely to want to get hardware that will let you use it. Even with the USB mic route, there's a preamp, it's just built into the mic, along with analog to digital conversion. The USB interface is more practical, because it gives you a headphone jack, often includes software, and will let you use a variety of mics, including that Sennheiser. Best of luck with whatever you choose-Richie
