The normal bookmarklets work with mobile Safari. The trick is getting the JS on your phone. If you make a new bookmark (for any page) and then change the URL to the right JS, it should work. Originally I had to email the JS to myself, but now I have it up on pastebin.

http://pastebin.com/mwSYY8mu

Here's what I use:

Add the post-by-email email address to your contact list, then use the Send To button in Mobile Safari, type "p-i" and touch the pinboard completion.

I second that. Hopefuly Maciej will put some work in place soon.