If you send a mail to:
send-to-omnifocus@omnigroup.com
They mail you back with an attachment that (on ios devices anyway) you can open in OF and it creates a task in your inbox with the title and text in your mail.
I use it all the time for remembering links or getting other fragments of text into OF.
You can get the desktop OF to scan your inbound mail in a variety of ways but it's fiddly to set up and you have to wait until you're home to use it. I tend to just use the re-mail address above since it's so convenient.