The real problem is that there are so many programs around that will do (mostly) what you want - with everyone having a favorite - that it's really hard to shake out a choice and get started.
Without doubt, the premier programs are Finale and Sibelius. I'd give the vote to Sibelius, because it seems to do a better job on tab - but both of these are $600+ programs unless you can get the "student discount."
The little brothers and sisters of these programs will do what you asked for now, and there are more shareware/freeware programs than even mudcat can possibly try.
Many shareware programs are limited to a single melody line. Unfortunately that's true of the Mid2Txt setup, which would otherwise be the ideal solution to "email" music. If you want to send music - any method other than snail mail - MIDIs are small enough to go as email attachments, and ANY decent notation program will make a MIDI from your notation, and will "make" notation from a MIDI. It's not even really necessary for everybody to use the same notation program.
ANY other transmission of a notation program file requires that the person you send a file to must have the same notation program in order to read it - or must at least be able to "import" the file into their "family" version.