juanclitton wrote:1) Am I correct in assuming that you have to access the database and download only the scores you need?
2) And that once it's downloaded, would I be able to open the downloaded scores even without wifi or 3g connection?
3) Are the scores totally free for download?
1) Yes, that is correct.
2) The scores are in PDF format, although some also come with attached finale (typesetting) files, but you don't need to worry about those unless you want to re-arrange the music. Provided your device (phone, Ipad, computer, whatever) has a program (such as Adobe Acrobat) to read PDF files, you can open them -- no wifi or 3g needed. Just save the file to your device and you can open it tomorrow, next week, or next year.
3) The scores are totally free -- there is no charge. However, you need to make sure that the score is legal in your country. Each country has its own "term of copyright", which is a number of years for which the work is protected. The usual ones are 50 or 70 years from the death of the last contributor (composer, librettist, etc.). So although you may find that you are able to download the score, it may not be legal for you to do so. Check the laws of your country. It might be a good idea to read our copyright page: http://imslp.org/wiki/IMSLP:Copyright_Made_Simple
The more detailed page is: http://imslp.org/wiki/Public_domain
Please note that this pertains to the country you are playing the music in. It doesn't mean that if a piece is in the public domain in your country of birth, you can play from a download or photocopy anywhere in the world. If your country is not listed on the two pages above, go to: http://en.wikipedia.org/wiki/List_of_co ... ght_length.
Please also note that posthumous publications, i.e. works published after a composer's death, are usually dealt with slightly differently. It can be as simple as the country's copyright term, but starting at publication, but it might also be different. You will have to check whether the work was published in the composer's lifetime, and if it is a posthumous publication, you will have to check how your country deals with it.