Have you tried to add .mpg to the file type list?
In Admin, go to the Global Settings tab then select Files and then click on New File Type

yeap done that need something that will play the file on the blog when I try to post a .mpg file it tells me that it can't post cause it isn't an image I'm using the photoblog skin could that be the source of my problem ?

Have a look at this plugin
http://forums.b2evolution.net/viewtopic.php?t=14397&highlight=audio

List of mime types...
mp3 => audio/mpeg
wav => audio/wav
wma => audio/wma
m4a => audio/mp4
midi => audio/midi
mp4 => video/mp4
wmv => video/x-ms-wmv
mpeg => video/mpeg
avi => video/msvideo
mov => video/quicktime

ok it plays audio but how do I get it to play video ?

Try this thread and see if it helps
http://forums.b2evolution.net/viewtopic.php?t=7825&highlight=mpeg

hmm can't find that plugins zip file other seems to be what I'm looking for

hey john, does the plug in you suggested work for 1.10.2 and also does it allow for users to upload files around 75mb?

I have version 2.4.0-rc2 and I'm trying to play an avi file. I've added .avi to my file types and here is the code I'm using, which works great for mp3 files,but for some reason I cannot get this to play an avi file.

<div align="center"><embed type="application/x-mplayer2" pluginspage="http://www.microsoft.com/Windows/MediaPlayer/" name="mp1" ShowStatusBar="false" EnableContextMenu="false" AUTOSTART=false width="400" height="350" loop="false" src="http://www.eample.com/example.avi"></embed></div>

mime types I've tried:
avi => video/msvideo
avi => video/x-msvideo

can some one tell me where I'm going wrong here?