>Please expect GPL as license or convince me for
>some other license agreement.

You are free to do as you like, of course, but the fundamental 
difficulty with using GPL is that no image containing GPL content, 
and linking from your materials to other classes subject to the 
Squeak license can be legally distributed to any third party (and 
arguably may not be usable -- but I didn't buy RMS' argument about 
that).

In short, the Squeak license and GPL are presently incompatible, due 
to the GPL's inability to distinguish a Squeak image from a DLL. 
Until we have sorted this through with RMS (and we are working on it) 
or decided that RMS is wrong about his construction of the GPL, it 
would be a grave error, IMHO, to build on GPL'd code for Squeak or to 
license code intended for use with Squeak under GPL.

The issue is not so much an ideological one about which is better, 
but rather a legal one: the two licenses are not compatible for 
software that is co-residing within a Smalltalk image.  There may be 
work-arounds if you determine the legal risk of an aggressive 
construction of the GPL to be acceptable, but the consequences are 
weird: you would have to take steps to assure that you don't modify 
the Squeak VM or base classes to link, directly or indirectly, to any 
of the GPL'd code.

The best work-around is to use BSD'd versions, if they exist, of the 
GPL'd software, or to ask the authors if they would be willing to 
grant a license to you under Squeak.  (I haven't had anyone say no 
yet, but I wouldn't expect RMS to approve).