Android: Paper-to-Go is a document scanner that uses your device's camera and converts the image into a PDF. The app is directly tied to OfficeDrop's cloud service, where the PDF documents get processed with Optical Character Recognition (OCR) to make any text in them searchable.
Processed documents can be searched from both the app and through the web site at any time. The app itself is free, but the service behind it requires a monthly fee after a 60-day trial.
A scanned document won't be text-searchable until it's been uploaded and processed, but you can always choose to keep the saved PDF on your phone since it can just be uploaded and processed later. This is especially useful for scanning papers inside large buildings, where a mobile data signal might not reach.
Documents don't need to be scanned first to be uploaded, either. There are over 25 filetypes supported for uploading directly to the account, which you can do from within the app. Paper-to-Go's OCR scanning feature isn't the same as the newly added capability in Google Docs for Android. It keeps the image as the PDF while making the text searchable, whereas Docs will attach a copy of the image to a text document.
You do need to create an OfficeDrop account to use the app, which it allows you to do the first time you open it. After the trial period, that service starts at $US9.99/mo for a single user, 10GB plan.
OfficeDrop Paper-to-Go [Android Market]