Currently Being ModeratedNov 3, 2013 2:07 AM (in response to Delmer Vaught)
If you are using iOS 4 (or earlier) there is no Software Update in Settings. That feature was first added in iOS 5.
To update you will have to connect your iPad to iTunes on a computer (preferably the one you sync with and backup to).
See here: http://support.apple.com/kb/HT4972
The iPad 1 can be updated to iOS 5.1.1