What is the font that they use on Facebook for the usual text, (not the font on the banner)?

[Ame]

I'm trying to change a Facebook page in paint and I need to know the name of the font or something close to it that I could download, preferably free.

[Damasta]

It's most likely one of these:
lucida grande,tahoma,verdana,arial,sans-serif
I found it by viewing the source code of the page and then locating the css file. That contains the data for how the page will look.

If you want to find it yourself, then go to the page with the font. Right-click on the page and select view source. You are going to see a lot of HTML code. You can either search for the font in the code, or you can search for the css page (Ctrl+f, then enter 'css' or 'font'). It will then have the font located somewhere in the text.