I'll write this entry in english hoping that some non-german users might be interested in this too.
When working with a lot of Projects in Eclipse for example on big modular applications you'll quickly notice that you quickly lose overview over your projects and have to look for them in the project explorer. This is especially bad for people like me who can't intuitivly work with alphabetically ordered things (I spend a lot of time thinking about wether the letter I'm looking for comes before or after the one I'm currently looking at).
To remedy this solution I've written 2 plugins:
The first one implements a "Go to Project" action anlaogous to the "Open Type" action.

Clicking ok in this dialog will select the Project in the Package Explorer, the Project Explorer and the Navigator.
The default key binding for it is Ctrl+Alt+Shift+Q (sorry for that, all the good combinations are already taken and this can be done solely with the left hand)
The second one implements a "Filter Package Explorer"

The Projects displayed are filtered according to the expression entered in the text field at the top. The is also useful when organizing projects into working sets (as you can filter them by name to do so). This plug-in is implemented in a very hack-ish way as the jdt Package Explorer is internal JDT api so it may change at any point. My plug-in extends the Package Explorer so it will break when heavy changes are made to it (or when the class is moved).
Both Plug-ins require atleast Java5 and probably Eclipse 3.4. They might work under 3.3 but I did not test that.
Download:
Go to Project Action
Filter Package Explorer
To install simply drop the jars in your "dropins" or your "plugins" folder inside your eclipse folder.
For the Go to Project action to work now rightclick your toolbar, select "Customize Perspective...", select the "Commands" tab and check "Go to Project" an icon will appear in the toolbar together with a new entry in the navigate menu and the shortcut (Ctrl+Shift+Alt+Q) will now work.
To use the Filter Package Explorer click Window->Show View->Other... type FPackage in the filter and double click "FPackage Explorer"
The Sourcecode for both plug-ins is included inside the jar. The source for the Filter Package Explorer is horrible due to it's hack-ishness please don't use it as a guide
edit: There is now a p2 repository available at
http://frz.cc/ecl add it to your update manager and you'll be able to install the plugins trough it
update 2008-12-08: I fixed some rather bad bugs in the Filter Package Explorer (broken design, filter not working) press update in your update center or use the (updated) download link above
update 2008-12-09: Changed the used listener from key to modify listener, this makes things work when you change the filter field using the mouse for example