I have to write a media release for the launch of a new product.  Can
you give me some suggestions as to how to go about this and hints on
what makes a good media release?

Dear Ehpc, 

Here are several helpful advices: 

How to Write a Media Release
by Ron Mader
<http://www.planeta.com/ecotravel/tour/mediarelease.html> 

How to Write Foolproof Media Releases
By Matt Bacak  
<http://ezinearticles.com/?How-to-Write-Foolproof-Media-Releases&id=70780> 

How to write a media release 
<http://www.irct.org/usr/irct/home.nsf/unid/BKEN-5KYHNW> 

Getting Free Publicity: How To Write A Press Release
Article by Karon Thackston
<http://pandecta.com/write_press_release.html> 

Press Releases - How to Write a Great Press Release
<http://www.publicityinsider.com/release.asp> 

How to Write a Press Release
<http://www.infoscavenger.com/prtips.htm> 

How to Write a Press Release
<http://www.ereleases.com/howtowrite.html> 

Luan Aten, How to Write a Press Release
<http://www.lunareclipse.net/pressrelease.htm> 

I hope this answers your question. Please contact me if you need any
clarification on this answer before you rate it. My search terms were
["how to" "media release"] and the same for "press release"