I am a contributor to the Spoken Wikipedia project. I do my best to keep spoken articles interesting using my own conversational style. I've been able to produce very good results with just a few simple tools:
A $15 Plantronics free-standing PC microphone
Audacity 1.3.7 beta - especially useful for noise reduction and improving bass
Levelator 1.4.1 - normalizes audio for a consistent sound level throughout the recording
A few tricks:
I wrap the head of the microphone in a cotton ball to reduce popping (hard P's), essing (hard S's) and "tinniness".
To reduce echo, I record underneath a comforter draped over two chairs. Described by one user as an adult building forts. :D
If you like my spoken articles, please feel free to recognize my work by placing a Spoken Barnstar on my talk page.