questions about ITHS

Ok, just now i became very fond of ITHs, I did not knwo about them or care about them till 5 minutes ago.

Here is what happened, I was standing around in a free room with my grabit on waiting for people to drop shit so i could grabit up. When some little shit entered the room bragging about his bow, saying how he was going to give it away, after a few minutes i opened a trade with him, the moment i opened trade i clicked the checkmark, lol to my surprise he mistakenly hit his checkmark as well. well this was no wf, it was a fricken ITH, 440/110 bow.

Ok now to the questions.

1) when someone says 110/60, what do they mean, what ITH are they refering to.

2) what should i suspect to get out of this bow, should i use it to level chars up fast, or should i sell it before it (might) be to late.

3) how rare is something like this, and what is the best ITH bow around?

thats it, thanks alot for your help