Background: There are several sites that I visit regularly on my iPhone that require me to log in. Unfortunately, the sites set cookies that expire at the end of the session. This unfortunately means I end up having to log in up to a dozen times per day.
Well, there are bookmarklets that allow you to view all cookies set by the current site, so I don't see any reason why this wouldn't be possible. If anything, you'd just need to enumerate/grab all the cookies, and then re-set them using a new expiration time/date.