I have an 04 gs500f and  just took the battery out but I have a few questions.

I unscrewed the battery from the pos, and neg cables and pulled the battery out, but I noticed there was a black tube attached to the battery.  I pulled it off but not sure if I did the right thing?  Will something leak out of the tube, should i cap it off or anything?
How about the battery itself, will battery acid pour out of the hole this tube was attacked too? Should I cap that off also?  Sorry i'm new to this and not sure if I did it right.  The bike didn't come with any owners manual.  But I do plan on buying one somtime in the near future.  thanks in advance.

That's just a vent tube. It just goes down the frame and vents in front of your right foot. Yes, you should have disconnected it as you did. No, nothing will now gush out from it. Of course keep the battery upright, but you are fine.

It's okay to disconnect when removing the battery from the bike.  It's the battery vent/overflow tube, it routes acidic overflow past all the important stuff like frame, wires, etc; leave the tube in the bike.
Fluid can pour out the spigot if the battery is tipped.  Don't tip the battery.

cool, thanks for the replies. 

BATTERY QUICK TIPS - Top off with distilled water only / charge no more than 2 amp hr / do not block battery vent while charging / negative is disconnected first - hooked up last / do not let battery freeze / charge once a month / do not store on cement / do not spill acid / have fun while you learn !

One last question.  Im going to be buying a battery tender, is there anyting I have to keep an eye out for when buying one?  Or would any cheap one from lets say walmart be sufficient?  thanks.

I have the  BATTERY TENDER myself . Just check to see that it charges at no more than 2 amp/hr and it switches to standby when fully charged. My HARLEY ridin bro just picked one at SEARS.