Yes, you can pursue a voice over career with only a USB microphone and a computer. Gone is the equipment of yesterday–no tape, no cassettes, no CDs. With your USB mic, your computer and Audacity recording software you can produce broadcast quality audio files and send them anywhere in the world in minutes.
The newer USB mics have two major improvements. The first is variable gain control on the mic to allow you to adjust the mic level. The second is a headphone jack on the mic that lets you hear your voice in your headphones without any delay or “latency”.
Finally the latest mics use new 24 bit/96 kHz A-to-D converters to provide pristine sound. These mics start around $100 and range up to $300 so you can get started on a low budget. Check out my updated chart of microphones–and other valuable information–on my home voice over recording page. Take a look at ’em