The "+" is Cellphone short code for International Access. If you are in the US, it just means that you received the number, and didn't enter it yourself (at least that is what I can tell).
So to call international from anywhere I just need + at the start of the number before the country code and I don't need to remember the local int. dialling number.
Skype and Cellphones uses the +(country code)(area code)(number) format. If you save all your numbers that way, you don't have to do anything different whether you are calling local or long distant.