Is there anyway i can send the thaiboxing from thailand down the internet line to my friend in new zealand ?

I have been looking at sling box but i'm not sure i can use it from thailand to new zealand .

Yes, you could use a Slingbox located in Thailand to stream to NZ (or anywhere else that has an Internet connection for that matter), but unless you have a DVR or PVR (Digital Video Recorder / Personal Video Recorder ) in Thailand your friend could only watch it in real time and not be able to "time shift"

It has been my experience (streaming from the US) that a recorded program plays better since the Slingbox can more easily control the buffering

Also remember that your friend will take control of your Thai TV while he is watching the Slingbox feed

Another possible solution is to obtain a TV tuner card for your computer, record the match, and then reduce the file size using WinRar or 7Zip and then upload the resulting file to a file hosting service such as Rapidshare, Megaupload, etc. Then your friend could download the file from the file host and watch it on his time schedule