But presence shouldn't be limited to the IM screen- after all most of our contacts are in our email address books. If presence is managed by IM, then shouldn't we link it to email? Microsoft's Windows Messenger is already linked to Outlook, but the more popular IM networks don't have direct links.]
AOL's AIM is a case in point. With millions of users (including technically everyone with an AOL email address), it's a popular tool inside and outside the office. I've worked in many places where it was a semi-official tool, with AIM IDs in the company phone book. AOL's AIM@work website is a statement to this, focussing on business uses of IM, and links to the traditional phone network and to web meetings.
Now it's released AIM Sync, a tool for linking AIM buddy lists with your Outlook contacts. Installed into Outlook, it will synchronise your contacts with your buddy list, so you can see if contacts are online or not - as long as they use AIM, and the email address you have for them matches the one they used to sign up to AIM. You can even use AIM to send text messages to their phone..
Not perfect, but at least it's a start.