Creating translation links with i18n

Wasn't sure where to put this, so I put it here. I'm trying to create a bilingual site in English and French, and I want to have a secondary links that switches back and forth between the two, "English" when I'm on the French side and "francais" when I'm on the English side. I don't want them to go to any particular page, just whatever page is currently being views, except in the other language. That struck me as the type of thing I've seen on countless sites, so I figured someone would have already asked about it, but I couldn't find anything. There was a way to do it in PHP in 4.6, but it doesn't work the same way in 5.1. Does anyone have any ideas, this is pretty much make or break for the project.

Another thing I was wondering is I've set it up so that the site uses one logo for the French side and a different one for the English side. The only problem is that the home page (whether I get to it from the French side, the English side, or externally) comes up as a the site-name, which is not language specific. Does anyone know how I can make the home page either www.sitename.com/?q=en(possibly followed by path alias) or www.sitename.com/?q=fr(possibly followed by path alias) depending on where I'm coming from. That too is probably make of break.

If someone could answer either or both of these questions for me they can have my first born. Thanks a bunch in advance.