If you noticed this banner after logging into basecamp recently, you are one of less than 1% of users that will need to change your login.
37Signals is ditching OpenID logins. I'm not surprised, as all the geeky features I wanted to take advantage of (ical syncing, API Integration, etc), seemed to take a lot more effort. 37Signals admits, "What we've learned over the past three years is that it didn't actually make anything any simpler for the vast majority of our customers. Instead it just made things harder."
Luckily, it's pretty easy to switch: