Look at the Fedora Liberation Sans typeface.

There's Liberation Sans from Red Hat, which is metrically compatible with Helvetica.

Why not just helvetica… It's going to look like it anyway.

Depending how close you are aiming, why not Univers?

There's also URW's Nimbus Sans L, which pretty much is Helvetica. A subset of it was released under a free licence to be included with Ghostscript. There are numerous (legal) derivatives floating around the web, e.g. GNU FreeFont.

Thanks to skoob. I checked the GNU FreeFont and FreeSans is the font I'm looking for. It is virtually impossible to tell FreeSans from Helvetica.

Thanx again