How Do I Update My iPad Software Without Connecting It To My Mac?
First, use your computer to update your iPad to iOS 5. To upgrade to iOS 5, connect your iPad to your computer and open iTunes on the computer. Select your iPad within iTunes and choose the Summary tab. Upgrade details will be listed there. If they are not, make sure you have the newest version of iTunes.
Once you have upgrade to iOS 5, subsequent iOS updates can be downloaded directly to your iOS device. Just launch the Settings app, click on General, then Software Update.