you must use VPN to get plugin.

To reply the Misagh that get GWT plugin  zip file , from Where?I have downloaded gwt sdk, but i haven't saw GWT plugin zip file .
To reply Babak and Amin I have installed it by using proxy in Eclipse but It given me "time out ..." Exception, And Installing from VPN , I truely don't know How to Use ?

easily you can use a p-r-o-x-y to download gwt plugin  for eclipse.
I have tried it and it works well.

On the GWT website itself, there's a link that you can download the zip package:
code.google.com/eclipse/docs/install-from-zip.html

But since it's probably filtered in Iran and Google doesnt allow access, you need to try something different:

1. download and get a proxy like Ultra Surf first.
2. Download a Download Manager, like Internet Download Manager and set it up to use Ultra Surf in its proxy settings.
3. Then, using the Internet Download Manager you should be able to fully download the zip file.

The reason I suggest using download managers like IDM, is that they support resume functionality, and VPN/Proxy programs often tend to drop the connection in the middle, which tends to not work well with eclipse  and can seriously screw things up. With IDM, when Ultra Surf drops the connection for example, you can simply reconnect and resume the download instead of starting from the beginning.

Download the GWT plugin  zip file entirely and unzip in the plugins folder of Eclipse. There might be a few more instructions that you should have to follow other than just unzipping the package, so double check with the GWT site before you do.

Either way, last I read that the GWT plugin was real buggy and kept crashing Eclipse while repeatedly trying to update some resources which took toll of the CPU. This also happened to me during a demo! Research this out before you give it try. This was about 2-3 months ago, which GWT confirmed the bug but I dont know if they have put out a fix for it yet.

Use a VPN or just set your proxy in eclipse  , that's how i done that .