I found the registry entry to change to remove the today window.
I closed aim, changed the key, and started it back up... no today window... so they haven't hardcoded launching the stupid thing.
Version for the people who don't know how to edit the registry**
( > denotes "then click")
Click Start > Run > Type "regedit"
Click HKEY_CURRENT_USER > SOFTWARE > America Online > AOL Instant Messenger (TM) > Current Version > Users > (the screen name you initially sign in with*) > MISC > double click the value of "ShowAimTodayWindow" and change to "0". (minus the quotation marks of course)
*I signed in with linked screen names and I only had to edit it with the one I sign in with from the login prompt, so the options for the other ones don't matter. (I'd assume.)
** If you do this and mess something up, not my fault. BE CAREFUL.