I'm not sure where to post this, but as the system I'm looking for should be written in php, I thought here would be ok. (Mod, feel free to move)

Just like wordpress for blogging, phpBB for forums, sugar for crm's, etc I'm looking for a system that I can use for selling your products online.

One should be able to browse products by category or searches, put them in a shopping cart, pay for it, etc.
Hoping the system support multi languages and written in php.

I was going to (probably still will) create a system like this msyelf, but if sth really good (and free) like wordpress, etc out there I first want to look into that.

Any well known and used software?