I sometimes shift the focus slightly and use agreement in a situation like this. Once it has been made clear that the agreement is about collaboration / cooperation / partnership, it is in fact just as much the fact that the parties have planned and agreed, or the terms / content of their agreement, that will influence their joint activities and bring new opportunities, enable them to benefit mutually, or whatever.

Rephrasing to introduce the phrase working together
or emphasising the samarbejde in other ways may sound more naturally English than slavishly cooperating or collaborating.
Both words have connotations in English which do not apply to samarbejde in Danish, and in a text like a press announcement, I think there is scope for that much freedom.


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Note added at 18 hrs (2010-05-12 07:00:50 GMT)
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Joint venture perhaps

Cooperation rings in my British ears of the Cooperative Movement. Great in its place, but this is not the same as two research institutes pooling resources and exchanging ideas.

Collaboration is a partnership, and is often based on a contract or some form of formal agreement. OK, so is this relationship. (´... indgået et samarbejde´)
I find in practice though, that neither word is used as frequently in English as ´samarbejde´ in Danish, and according to my text, I sometimes try to find other ways of expressing what is going on in each case.