Hi Robby,
You can get the bundle license for 1Password, which will run on both Windows and Macs. You can use the single-user license for all of your Windows and Mac computers as long as you're the only 1Password user. The cost is $59.99.
1Password for Windows does have an extension that'll run in Internet Explorer 7, 8 and 9. It should work on Windows XP with Internet Explorer 6. You can download the trial from their site and try it for 30 days without any limits. The link is here:
http://agilewebsolutions.com/downloads
1Password for Windows doesn't support Safari yet, they plan to support it in a future update but they do not have a timeframe on it.
For your iOS products, you can also grab 1Password Pro for $15 which is a universal app that runs on all of the iOS products.
You might want to contact the support team at
support@agilewebsolutions.com, they might do something special for you if you want to get both apps.