I have some copied content on my site, 2-3 post, should i leave it since is already indexed or remove it to prevent a panda hit?
It depends on where it came from.
Did you swipe it or is it from an article directory or other source of the like?
If it is from a directory or news source, it is easily fixed by making it an original review style post by saying something along the line of the following reference:
" Hey guys, just found this really interesting article/news bulletin/blog post and thought I'd share it...be sure to check out the ' author's name here ' over at ' his/her blog name here ', then stating something nice about their information ONLY if it is relevant and is really good and of use to your readers. "
This builds outbound links as well as authority of you being in the know in your market, as well as being able to freely use anyone else's content legally, as you are stating the source which it came from.
Always email them through their site email so that you can share that you've linked with them and give them the option to tell you if they don't approve, so that you can take it down. This covers your butt if they scream any legal threats, as long as you do it this way. Don't Modify this method or they can and will get your into trouble.
if you've copied/pirated the content, modify the post to the above described method and you'll be fine and gain authority, as well as rep points with the original content owner.
Everyone wins.
Hope this helps.