#1
I was wondering, when you don't use capo playing songs that uses a capo, it would still sounds "ok" right? it will be just in another key?

I just played wonderwall without a capo and it didnt sound that bad
#2
yup, it'll just be in a different key.
although in many cases, depending on your range and the range of whoever usually sings it, it'll probably be harder to sing because of the different key..
#3
Yep. Most songs that are tuned down half step I also just play in standard. If you're playing with other instruments this could be an issue, but for just playing on your own you can play without changing tuning down 1/2 step or adding capos, just adjust the singing accordingly and rock on
My Gear
Epi Les Paul
Roland Microcube
Boss DS-1 pedal
Shure SM57
M-Audio Fasttrack
#4
If you mean moving the capoed piece to the nut (as the capo is there) then you'll be playing in a different key. If you were playing the same position but the capo's removed then you might have some open strings in your key.
#5
Options:

1) Play it in a different key.
2) Use a finger to barre where the capo would be
3) Transpose the chords. I.E. If it's capoed on the 2nd fret and the chord progression is written as G, C, D relative to the capo, than you just take those chords and write them a whole step higher, making the actual chord progression in that example A, D, E.