Is it too confusing for users, to have the right sidebar on your main page, and on all others left sidebar ? Thank you
I think that consistency is one of the most important heuristics for web design. So I do believe that if you were to do some usability tests, a lot of the test users would complain about something like that.
Is there any good reason why you have to do it?
The Web Standards Checklist is there to help around such questions and more others.
Also have a loot at Web Design Standards.
Remember client first then others.
You should always strive for consistency in your main navigation. If the sidebar looks the same on all pages, it's probably best to keep it in the same place.
I, against others, would say it depends. If you have visually different sidebar on landing page and on others, plus absolutely main navigation (:]) is somewhere else (e.g. top), you could go for it - i.e. sidebar with big pictures on landing, then informative sidebar on subpages won't confuse users (much).
On the other hand, if others are right, and your sidebar contains main navigation and looks the same (or almost the same), changing it's place probably will confuse users.
So, if it's the same thing (same layout, same content), keep it on the same position. If it differs (it's visually more rich on landing i.e.), the change won't confuse users so much - if you stay consistent on subpages.
That is my opinion :]