If you had Logic 9, it would be really easy with Varispeed...
I would recommend using the Transform section of Logic 8 and experimenting with algorithms. I've been using L9 for too long now... I've almost completely forgotten the process... I know that the "Classic" algorithm is the opposite of what you want... but I believe there's another algorithm there that will do what you want...
What you'll have to do though is record a region and then edit it afterwards... if you just want to do it note-by-note you'll have to use "split/demix by note pitch" after recording the region to separate the individual hits.... It's possible, and should work with a little experimentation... but probably not quite as intuitive as you'd like..