playing videos on a tv from an iphone.

http://store.apple.com/1–800-MY-APPLE/WebObjects/AppleStore.woa/wa/RSLID?mco=184EAE7D&nplm=MB128LL/A

After doing a lot of searching online I found this cable. It says it does what you want. Good luck!

You have the choice of component (Part no. MB128LL/A) or composite (Part no. MB129LL/A) video-out cables from the Apple store that are in the Cables and Docks category of the online Apple store. If the link doesn’t work search by the part number or go to the section through the store homepage . The item page will show iPhone compatibility for the right one.

Several caveats:
-The older A/V cable that went from the headphone jack doesn’t work with the iPhone or any of the current iPods. The new ones connect through the bottom dock connector.

-You need to have the iPhone 1.1.1 update installed for TV out functionality. If you have a hacked iPhone it will disable that functionality. You can update an iPhone simply by syncing with iTunes while you have internet connected.

as far as i know, iphone has TV out cable, the Apple Composite AV Cable which can be used accross all the ipod product line.
have fun!