Thankfully, iGoogle lets you export your settings and gadgets as a XML file, which can be easily processed and transformed into an OPML file.
Here's what you need to do if you want to export the feeds from your iGoogle page in the OPML format:
1. Log in to a Google account.
2. 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.
3. Paste the code below and 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.)
4. Save the output in a XML file: igoogle-subscriptions.xml.
To import the file in Google Reader, go to Settings, click on Import/Export and upload the OPML file. In Netvibes, the steps are less obvious: Add content > Add a feed > Import. Most feed readers have an option to import a list of subscriptions.
I tested the script for converting iGoogle's backup file in IE7, Firefox 3, Opera 9.5, using Google Reader and Netvibes as destinations.
Related:
Import OPML files to iGoogle