freeware? mmm... I don't know any, but if you google ti you'll find lots, sure. However let me suggest you some non-free software but it's very good for writting music (and of course, you can import midis and modifiy and print them).
Finale (and other programs) from Codamusic Very good program, a bit difficult to use if you're new and want to create and modify files. Easy for just opening a midi and print it.
Encore, from gvox Very simple and intuitive program. You get nice results quickly. Quite limited, compared with finale. If you only want to open and print midis, get encore, it takes less space (but, again, it's more limited, what you print wont' look so professional as with finale)
Sibelius similar to finale. I haven't worked very much with this one. In the web page, they say it's easier to use than finale, but I'm used to finale and I find sibelius a bit dificult (maybe distinct).
None of them is free, but you can download demo versions of the first and third one. For encore I dunno if there are demo verions (maybe).
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