YES there is. if you aren't rooted already do it (because an accelerated kernel makes it faster and root is just plane sexy) and download HDMwIn from the market.
I really liked HDMwIn. Took some getting fiddling to figure it all out with the settings and the screen rotation and all - but once you do, it does a good job. Kick up the resolution in it - and go nuts playing Angry Birds on your big screen.
You just need the HDMwIn app and a cable. The MicroHDMI port of the EVO will also push sound. You'd probably have to look around and see what kind of converters are available for taking your HDMI into something else. Something like this, I suppose?
http://www.amazon.com/HDMI-RCA-VGA-Cable-1-8ft/dp/B002ZUI68G/ref=pd_sxp_f_pt
Read the reviews. That will not work. Think about it. HDMI is digital, and RCA is analog. It's like trying to plug a pair of headphones into a TOSLINK fiber port.
Sadly, digital to analog converters can range in price depending on how and what's done. I know that high-end HDMI to analog converts can cost hundreds if not thousands of dollars. For example, this one here is $300. And it doesn't even have any reviews, meaning nobody's really bought it yet.
Honestly, downscaling HDMI to composite is like trying to play Crysis 2 multiplayer on an Apple II over a 19kbps dialup line.
what rom/kernel? what message are you getting (if any) on the phone/tv?