I'm working rapidly towards finishing up Silverlight in Action, Revised Edition. As part of the work for this, I find myself taking screenshots pretty regularly.

For a print publication, you want your screenshots to be the highest resolution possible. A screen is usually 96dpi, while a book is 300, 600 or more dpi. One way to handle the difference is to just design big: use big fonts, big buttons etc. However, Silverlight 4 responds to the browser zoom settings, so you can just use that.

Screen shot at normal resolution (for my RichTextBox section)

Screen shot with the browser (IE8) zoomed in 200%. It's a big image, and will crop the right when viewed on my site, but that's ok.

The second image is going to work much better for a print publication. The text is smoother due to the higher DPI; it's not just a bitmap scale, Silverlight is actually rendering the content at the higher resolution.

You can use the same technique when doing other screen prints of browser content, but it's good to know Silverlight plays nicely with the settings.