I am trying to determine the approximate value of my company (an
internet marketing firm). The ultra-conservative business plan
indicates 5-Year EBITA as follows:

2005-$90,574
2006-$599,983
2007-1,463,123
2008-2,640,614
2009-4,191,980

Based on the fact that the business is active (commenced July 2004),
is generating revenue, and has acquired "name-brand" clientele, I have
been approached by venture capitalists interested in providing
start-up capital.

Thank you!

I don't have an answer myself but if you ask this question in a few
webmaster forums I can promise some seriously thought out answers. 
Try ozzu.com or webmaster-talk.com both are great resources.  Also if
oyu truly think your company can grow that fast you should try an own
as much for yourself as possible and maybe get a business loan rather
than investors because investors, well the smart ones will require a
hefty return on their investment.