making href "login" that turns into "logout" in respect 2userstatus

I want to make a hyper text that says login or something of the likes that directs the user to a page to log in. upon submission I would like them redirected to the home page. I would like the hyper link to say either log in or log out in respect to weather the user is logged in or logged out. Just like any email website. I’m very new to all this, but for anyone who is willing to possibly check out my site, click.balloonmaster.com, and give me a tip or two it would be more than appreciated. I’ve tried reading through the source code from other sites to model it after, but I’m not formally trained, and most of it I don’t understand. I’m proud of what I’ve learned on my own so far as well as my first website. Thank you in advance ??