What is the difference between these two cameras. I am based in Australia and the two companies which i would be able to access this camera from sell it as the JVC GY-HD251E, whats the deal?

Here are the links:

http://www.videoguys.com.au/scripts/prodView.asp?idproduct=2186
http://www.new-media.com.au/JVC-GY-HD251-Professional-HDV-Video-Camera-pr-1933.html

If the 100 product line is a good comparison, this is just JVC's nomenclature. The E is the HDV 25/50 model and the U is the 30/60 model. Being in Australia, you definitely want the E for downconversion to PAL purposes.