Hosting a conferenece call i will be able to use skype out and call regular phones and ad them to the conference call like you can do on windows.

Is this possible on the mac version?

yes

how is that done?

I don't use a Mac, I only know that it can be done

I been trying for couple of hours here now and it seems that option is Windows based only

apparently you have to add the number as a contact before you can add the contact to a conference call (silly Mac deficiency if you ask me), but once done, all you need to do is drag/drop the contact to an active call window or right-click and select 'Add to Conference'

update: it does not appear that the current Skype client for Windows allows you to add 'adhoc' pstn legs to a conference call either -- you must add the number as a SkypeOut contact first