I am using wordpress twenty ten theme in my another blog. I was facing a difficulty to increase the width of sidebar of the twenty ten theme. Actually I want to insert one of the adsense ad there and it was not possible to do the same with the existing margins of the theme. I searched a lot and experiment a lot. At the end I was successful. I want to share the same that how I increase the width of sidebar of twenty ten wordpress theme. Here is the method:
Step 1: First login to your blog and go to the dashboard
Step 2: Go to the appearances
Step 3: Look for Editor in appearances. You may be in the style.css page
Step 4: Look for the lines
margin: 0 -320px 0 0; (Change your existing setting to this one)
margin: 0 340px 0 20px; (Change your existing setting to this one)
width: 300px; (Change your existing setting to this one)
Step 5.Update it.
I hope now that the there will be increase in the width of sidebar of your twenty ten wordpress theme
You can check the same in my second blog http://managementation.com/brand-strategy-decision/
All the best.