I’ve been playing around with Sign It!, a great little app for the iPhone, this past week. Sign It allows you to open PDF files from multiple locations – from your email, from a URL, from your computer, or from a drop created at Drop.io. Once you open the file, you can do a couple of things with it – you can insert text, a signature, a custom stamp, or a date and time. After you have saved it, you can then attach it to an email, upload it to a Drop.io drop, or sync it to your computer. I wish there was a way to attach the signed PDF to the original email, but so far that’s not an option with the iPhone. Still, this is a nifty tool to use if you need to sign or other wise annotate a PDF file but you’re not anywhere near your computer.