Where can I find a free internet site for DIY garden yard designs?

This is a good one Just register and log in to use it.
Use Lowe's Landscape and Garden Planner to help build the yard of your dreams. With our design tool, garden and landscape planning are as easy as clicking and dragging.
http://www.lowes.com/lowes/lkn?action=pg&p=Down_to_Earth/GardenPlanner/gardenplansplash.html

Here are three sites that might help you depending on what you are looking for, I love these sites because you can click on the video's for the garden designs.They are great for just starting out with a garden design or just getting fresh ideas for freshening up your old garden design and seeing what they will look like, too. I plan on redoing my garden next year and all of these sites, I find will be helpful to me and I hope they will be for you, too. I also like these sites because they are, FREE,FREE, FREE! Ha, ha, Faira

http://www.the-landscape-design-site.com/
http://www.curbly.com/DIY-Maven/posts/1496-FREE-On-Line-Garden-Planner
http://www.applegategardens.co.uk/

Here's a free interactive landscaping website from Better Homes & Gardens. You'll have register to log on to their website (You don't need to buy anything or subscribe to their magazine)."Plan-a-Garden lets you design anything from a patio-side container garden to your whole yard. Use your mouse to "drag-and-drop" more than 150 trees, shrubs, and flowers. Add dozens of structures like buildings, sheds, fences, decks -- even a pond." You may also have to close their magazine ad. by clicking on the x
http://www.bhg.com/bhg/story.jsp?storyid=/templatedata/bhg/story/data/planagardenhome_03022002.xml

Here's a slide show that can give you some ideas:
http://www.bhg.com/bhg/slideshow/slideShow.jsp?slideid=/templatedata/bhg/slideshow/data/frontyard_flowers_032604.xml&page=15

BBC Gardening- Virtual Design
http://www.bbc.co.uk/gardening/design/virtualgarden_index.shtml

Landscaping design:
http://justgardeners.com/hrsc/articles/art_landscape-design.html (This site contains a gallery of forum users's own pics too.)

Landscaping Plans from HGTV:
http://www.hgtv.com/hgtv/pac_ctnt_988/text/0,,HGTV_22056_60914,00.html
http://www.hgtv.com/hgtv/gl_landscaping_design/

Hardscaping:
http://www.hgtv.com/hgtv/pac_ctnt_988/text/0,,HGTV_22056_60415,00.html?affiliate=blocker&omnisource=landscape%20gardens&c1=Garden%20and%20Landscape&c2=Google&c3=Landscape%20Design&c4=landscape%20gardens&c5=Paid%20Search

Top 10 Tips for Do-It-Yourself Landscaping:
http://landscaping.about.com/od/designexamples1/tp/do_it_yourself.htm

Easy-care perennial rock garden, plus links to kitchen gardens, wildflower gardens,etc:
http://www.bbg.org/gar2/topics/design/2006sp_rockgarden.html
Cottage garden sample plan:
http://www.capecodconnection.com/garden/plan.htm

Perhaps you can get some ideas from this video of low-maintenance, low-water perennials in this garden, using native plants, ornamental grasses, Coneflowers, Salvia, Sedum, Coreopsis, Gayfeathers, Daylilies, etc.
http://video.yahoo.com/watch/946018

Images:
http://images.search.yahoo.com/search/images?p=landscape+design&rs=2&fr2=xpl&_adv_prop=image&ei=UTF-8&fr=ush-ans&vf=

http://websearch.about.com/od/dailywebsearchtips/qt/dnt0504.htm