Open this page, right-click and select “View source” (for Internet Explorer), “View page source” (Firefox) or “Source” (Opera). Copy the entire content of the file to the clipboard (Ctrl+A, Ctrl+C). Alternatively, download iGoogle's backup file and open it in a text editor.
Paste the code in the box below, then click on “Convert to OPML”. (If you are concerned about sharing private data, you should know that this is just a client-side script that doesn't store your data and it doesn't send it to a third-party service.)
Save the code in the text editor file on your desktop (File > Save As…)