Any easy way to make a microphone booster?

[fpelectro]

I found this auction on ebay that is selling a pen microphone with a 2-stage pre-amp and active audio booster circuit which increases sensitivity by 10 times over standard passive microphones.. I would like to know how to make this type of booster to attach to any microphone, so here are my questions..

1) How would I build it?
2) what parts will I need and wheres the best place to buy them?

I dont mind reading, im new at this so please bare with me.. all your help is appreciated..

thanks

PS. here is the ebay link to the product im trying to copy, this guy is very expensive unless this is something special that I dont know about?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3204&item=5526586242&rd=1&ssPageName=WD1V

[audioguru]

Hi FP,
Welcome to our forum.
That pen mic has a 2 stage pre-amp that could be just 2 transistors. Even a single transistor can easily give a gain of only 10. It probably uses an inexpensive electret microphone element available at large electronic parts suppliers. My Newarkinone catalog has 30 to choose from.

National semiconductor has new subminiature mic preamp ICs. they are designed to be included inside small electret microphone elements. Maybe an electronic parts supplier has these mics. National's link is here and it has links to their datasheets:
http://www.national.com/appinfo/amps/microphone.html

How are you going to keep the input of your recorder from overloading?
What if you are recording the low level voice of a person that is about 4m away. If you or the person beside you speaks, the level will be much louder and your recorder might overload.

[fpelectro]

Thanks for the links audioguru, do you have any plans for the 2 transistors that could easily add 10+ gain to a microphone? this is what I am looking to do. Please keep in mind I am new at electronics.. thanks