If anyone loves excel like I do, you'll love this spreadsheet I found.
All of the weight/size data was already in there when I downloaded this, so don't think I'm that person, hah.. But the instructions are at the top, just fill in your information in the white cells, the gray cells are formulas so don't type in them.
I changed the date column to automatically enter the date for every monday of every week.  If you change the date in the first box that says 05/05/2008 then the rest of the boxes beneath it will auto populate for a week out.  
The spreadsheet also has charts, if you see the tabs at the bottom, it will chart your progress for you!
Very handy!
I've attached both the chart for Women and Men, just in case anyone has a man at home that wants to chart their progress :)
Ps - There are a lot of other templates for this type of stuff (Including these same 2 spreadsheets but in Metric, for those folks not in the US) here: 
http://office.microsoft.com/en-us/templates/results.aspx?qu=diet&av=TPL000  
- Joleine