Question about using ac adapter all the time

Hi !
I just wanted to know if its ok if I leave the computer connected all the night (to recharge the battery) with the ac adapter?? and what thing is safer, to discharge all the battery each time I use the ibook, or can I charge it if it is with 35% or 50% or 66% (whatever)?? I read in other forum, that I should wait to the battery to discharge at almost 5% and then recharge it!!
Thank you! and sorry for my english =S

I would (and do) follow Apple's advice…
http://www.apple.com/batteries/notebooks.html

Thanks! I think that I should follow Mac's advices!

thanks again and for the response.