Setting up OmniFocus
If not turned on already, go into OmniFocus' preferences, go to the Mail settings and use the check box to create the Mail.app rule to process Omnifocus actions in the inbox.
Writing the bookmarklet
Here is the initial code for the bookmarklet:
The procedure
- If you use Google Apps, you need to replace the trailing mail in https://mail.google.com/mail/ with a/YOURDOMAIN.COM/ so it becomes https://mail.google.com/a/example.com/?view etc.
- Add your email address where indicated
- Copy it all
- Right-click on your toolbar and click new bookmark
- Give it a name (e.g. +Omnifocus)
- In location paste the code you copied from the text box above
- Click OK
That's it. Next time you are on a web page that you want to save for later, simply click the bookmarklet button. The email will pop up. you can change stuff, added extra text into the body field (which gets used as the note) and press send. The item will end up in your inbox (the task name will be prefixed with [Web clip] so that you can easily spot them/search for them.
Some things to know
Your destination email provide might not support emails like name+omnifocus@example.com so you may need to use the other way Omnifocus allows, which is to prefix the subject with something as described in the OmniFocus preferences.
If you didn't select any text on the page, the document title will be used as the task name. If you did have some text selected on the page, that will be used for the task name.
Customising the bookmarklet
You could change the prefix ([Web Clip]) to something else, or remove it completely.
You can add contexts (for example, you may think that everything that you will be clipping needs to be done online, so you need to add @online after the subject
You can add start dates, due dates. All the things as outlined in the OmniFocus user manual.
If you find any problems with it, have any difficulties in customising it the way you want (I certainly did!), please leave a comment below and I'll see if I can help.
Comment
Thank you Paul!
a little extension for those who like to add selected text into the email (adapt the code as described above!):
[removed](function(){x=document;y=window;if(x.selection){sel=x.selection.createRange().text;}else if (y.getSelection){sel=y.getSelection();}else if (x.getSelection){sel=x.getSelection();}if (sel==''){sel=document.title;}m='https://mail.google.com/mail/?view=cm&fs=1&tf=1&to;='+encodeURIComponent('YOUREMAILHERE')+'&su;=[Web clip] '+encodeURIComponent(sel)+'&body;='+encodeURIComponent(document.title)+' at '+encodeURIComponent(document.location)+' text-snippet: '+decodeURIComponent(document.getSelection().replace(/\s/g, ' ').replace(/ {2,}/g, ' ' ) );w=window.open(m,'addwindow','status=no,toolbar=no,width=575,height=545,resizable=yes');setTimeout(function(){w.focus();}, 250);})();
If there is no text selected before pressing the bookmarklet there is nothing added but "text-snippet:" (remove it if you like 
greez JoH