IMS 4.0 was released a few days ago. I do not try this version because its 3.1.1 Personal meets my basic needs and helps a lot. I cannot find any information about 4.0 Personal so I guess that there is no 4.0 Personal. (I was wrong)
I do not have Outlook at home, and that is why I did not buy a Pro license.
If you want to know what is IMS, you can find a lot of videos at its homepage.
(Updated: Thanks for the comments from ClearContext guys and thank you for providing me a license so I can continue to enjoy this great product.
I am going to write a longer review in 2008 to report how this product saves me from drowning. Stay tuned.)