For diapers- check stores like Trader Joe's, Whole Foods, Wild Oats, and even Woodman's Market- they have ones with flushable liners sometimes that are biodegradeable and really reasonably priced. Target is also carrying more eco-friendly cleaners and things, they might have something.
For you period, eBay has work-at-home-moms who make cloth pads if you want to try that, or I've heard the DivaCup is good with some practice. I like seapearls- they are natural sea sponges with no chemicals that you dampen with water and insert like tampons. To wash, you rinse them in water and then let them soak overnight with a little bit of hydrogen peroxide in the water to bleach or tea-tree oil to disinfect.
Here is a link: http://www.jadeandpearl.com/catalog/index.php
You might also want to join a Yahoo group- there are some really good ones on how to live a "greener" life, and here is a great site on how to parent more earth-friendly with lots of various sections including how to make your own cleaners, etc!
http://www.mothering.com/discussions/index.php (scroll 3/4 down and look in the Mindful Home Management section if you want to skip the parenting forums!)
Congrats on your decision to live greener and Thank You!!
-Amanda