I use
www.menus4moms.com as a basic menu plan, and plan for 2 weeks at a time, since dh gets paid every other Thursday. So sometimes I'm using last week's and this week's menus. I only plan 8-10 meals for two weeks, since we'll have mac-n-cheese nights or leftovers or whatever. If there are things I know my kids won't like, I look in the archives or in my cookbooks for an alternative. At M4M, they provide a PDF grocery list, but I like to figure my local prices so I've developed my own Excel spreadsheet for groceries (I think I can link it in Google Documents if you're interested). Wednesday before payday, I go through the recipes I want to do for the next two weeks and make a note of anything I need to buy, and enter it in my spreadsheet with at least guesstimated prices.