So... This really good friend asked me out and I think that I may have...

Try hanging out with him. See how it goes, whatever. Then over the next few times you hang out, just change the setting from a friendly to a more "just the two of you atmosphere." If you decide he's the guy for you, then ask him to go for a walk or call him later and after you have your usual "conversation-starter talk," you could say: "you know, I'm really glad we got to spend some time together." See if that's a big enough hint for him to make a move, if not then you got to open up a little more, but not too much. Just to the point, and "civil and elegant sounding"; not "nervous and desperate sounding."

See what I did there. I broke it up into steps to get a read along the way. It happened the same way in my poem. Did you see how it ended.

And think about what originally attracted you to just being his friend. That feeling might be getting a stronger now that he asked you to hang out and your thinking about it a little. There must be some good qualities about this guy that are now starting to stand out since you've thought about it.

From your short details it sounds like you have a good foundation for a relationship ... "From best friends to lovers and From lovers to friends" ... I forget where I heard that, but best of luck!

Not always guys need to be told things. It works better if you show the guy you like him, And not just tell him. At least show it first and then tell him later. Going out with him would be the first step of showing your feelings:)
GOOD LUCK