If you’re new to Yfrog, sign up for an email address on the site, which you can do through OAuth. After that, open a new text message on your iPhone and select a photo or video to upload. Then just type in your Yfrog email address and hit send. You can even type in your own message within the MMS text to add a caption to your picture or use the “@” reply function to notify someone that you uploaded the photo. Other than its slight sluggishness — it took about a minute for the photo to finally go through — the main downfall of Yfrog’s MMS capability is that “Multimedia message” is written before the link to your photo, which isn’t very aesthetically pleasing. Overall, the new Yfrog capability works just as it promises, but for now I’ll stick with Twitpic and Echofon.