Did you ever think of your finger as a legal signing tool? Softsign for iPad (free for a limited time) offers a PDF annotation tool for iOS that allows you to sign legal documents via a touch screen.
Developer Tom Hodgson points out that a variety of laws implemented more than a decade ago made electronic signatures legally valid in the US, the UK, and beyond. The 2000 United States ESIGN act specified that e-signatures could be accepted as equivalent to a written signature for commercial transactions. The EU has the 1999/93/EC Directive on Electronic Signatures, and in the UK there is the Electronic Communications Act 2000.
The first time you use the app, you're prompted to enter a master password. This password goes into effect whenever the screen goes idle or you enter or leave the app. It ensures that no one is going to use Softsign accidentally by picking up your iPad.
Once you've authenticated, you can review the PDF agreements that have been sent to you and sign them, both by entering typed text elements and by signing items. The signing screen provides an interactive drawing session letting you create as many strokes as needed to build your signature. Handy undo support means stray marks can be removed before adding them to your signature.
Softsign has clearly spent a lot of time thinking about the user experience. You can easily drag elements around the screen to move them into place just-so, or to resize or delete them. This is one of the best iPad direct manipulation GUIs I've encountered in that regard.
I'm slightly less fond of Softsign's annotation system, but I understand where it comes from. The designers needed to adapt tasks to a touch-only system without having to add complex gestures or overly train their users. They did this by adding a lot of menus. These are quite pretty to look at, and simple to use, but I wish you didn't have to drill up and down quite so much.
Softsign allows you to mark up PDFs, not just sign them. When you enter annotation mode, it uses a series of (modal) pull-down menus that allow you to adjust the pen size, to navigate through the document, and to perform basic edits.
Once you're done, (tap Done), you save your changes (with optional password protection) to file and enter a screen that allows you to email and print the file. Softsign offers integrated "Open in" features, letting you export your signed documents to AirSharing, Dropbox, or other applications that connect outward to the internet.
Adding new documents to Softsign couldn't be easier. Just drop items in through iTunes or email them to yourself and use iOS Mail's "Open in" option to move PDFs over to Softsign.
On the whole, Softsign is cleverly built, offers well thought out features, and was straightforward to use. It is being offered for free for a limited time. TUAW suggests you take advantage of this offer while you can.
[We covered SignMyPad a while back, a similar app developed by former TUAW contributor Justin Esgar. SignMyPad is now $3.99 for the basic version, and $19.99 for the GPS-enabled Pro version that formerly cost $99. –Ed.]