Short answer: When Debian Squeeze is actually released (for a recent enough Qt to build OMEdit). You could also try the Ubuntu repository, which already has it.

Ok, i want to try: Can you tell me how to install?

We need to ignore the libqt4core (>=4.7) dependencies then.

I tried to use equivs to do that. That didnt work for me.

Maybe you know how to do that?

dpkg --ignore-depends=package,... --install omeditXXX.deb

Fine! That brings OMEdit to my disk!
Unforunately, it didnt start, saying:
undefined symbol: _ZN9QListData11detach_gro

Ok, I finally installed Qt4.7 from the experimental repositories and reinstalled OMEdit.
Now, it starts without problems. Running simulations works too.

Just one, for me BIG, issue: The programm window doesnt fit to small screens (1024x600). The window jumps up and down regardless where you are clicking to. Resizing the window doesnt work as well. I belive this is a Qt-Issue since digiKam shows the same behavior on my small laptop.
Maybe you can solve this shrinking the initial programm window to fit small screens?

That would be great! Thanks!

I made the following diff. It seems to work rather fine (it starts at a size appropriate for a larger display but may be resized if the screen is too small). You might get scroll bars in the editing area though, as it becomes quite cramped there.
-    this->setMinimumSize(950, 670);
+    this->setGeometry(0, 0, 950, 670);
+    this->setMinimumSize(400, 300);

The new packages should be in <15 hours if all goes well.

Perfect!