If like me you use the AMM plugin in WordPress: http://www.sozu.co.uk/software/amm/ , then you will have noticed that due to changes in Amazon's policy, searches made to add new items to your lists within the plugin stopped working a few days ago (existing items on your lists should still work fine).
The reason for the plugin not working is that all requests made to Amazon's API now need to be signed using a secret key.
The other problem that this raises is that to stop one user's secret key from being revealed, every user of the plugin now needs to sign up as a developer with Amazon to obtain their own secret key. I have checked & other WordPress Amazon plugins also now have this requirement.
I've been in touch with the plugin's author & worked out a quick fix to this problem which I have running now on my site with no major issues.
It should be incorporated into an updated plugin release soon - if anyone needs the revised code urgently let me know & I'll send it to you by email.