I recently startet scuba diving and I want to buy a housing for my ixus 860is camera, but after searching the internet i´m a little bit confused.

I think i´m supposed to buy the WP-DC17 housing. I found these 2 links:

Canon WP-DC17 Housing f/ Canon PowerShot SD870 IS
Canon WP-DC17 Underwater Case for Ixus 860 IS

Is it the same housing for 2 different cameras??

Thats indeed a bit confusing, but it is one housing for one camera.

Canon has different names for the same camera in Europe and the US.
In the Europe all the compact cameras are called IXUS whereas in the
US it is the powershot series. To add more confusion the numbers do
not match in many cases. That means the Powershot sd870 IS is
actually the IXUS 860 IS in Europe.

ciao Lars

PS: http://www.dpreview.com/reviews/specs/Canon/canon_sd870is.asp

Ahh, that explains it.

Thank You