The only decent QT export option from Premiere 2 is H 264 (mpeg4) and that requires the audience have QT player 7.x. There is no preset for this, so open the default QT Format/preset in the Media Encoder. On the lower left side are some tabs, start with Video. Change the Video Codec to H.264, change your Frame height and Width. scroll down and change the Bitrate to 600 kbps.
On the Audio tab, leave the default QDesign Music 2, but click the Options button and change the bitrate to 48 kbp/s.
I prefer to use QT Pro to do this encoding…many more options and better quality. Although I use Windows Media Video most of the time.