Well, the little engine that could is running out of steam. As the release dates for this year's essays approach, I find it harder and harder to get actual work done.
Application deadlines are beginning to role in, of the choice schools, only one thus far:
Wharton: Deadline for R1 - 13 Oct 2005 Release Date - 22 Dec 2005
So at least part of my fate will be decided by December.
Transcripts: Current bit of advice is to get started on requesting transcripts. Although take note, many top MBA's have their own form which must be attached to the transcripts when submitted. So, since this form is only contained in the application, make sure to download last years application. Unfortunately, they are not always available (especially now that all 3 rounds have passed for '04 - '05). Transcripts should be free (at least they are at Notre Dame) so get extras just in case.
Essays: Not as though it is news to anyone, but at this point you should have already started the essay process if you are planning on a R1 app. What has worked out thus far for me (and a fairly good approach) is to sit down and study one school (web page, blogs, forums, etc.) and really find out the specifics of the school. Especially pay attention to the little details, if you can get those down (like clubs, culture, school atmosphere) your application will look that much better. This is, after all, a sales pitch so you have to know the customer.
Once you have a good idea about the school, grab last years essays and write some good outlines. These you will be able to use for the upcoming essays.
I give this advice assuming that you have read at least one or two books about MBA strategies (I'll have to put up some recommendations later). These will give you general pointers (like key themes that every school wants and exactly what kind of experiences, examples to include) as well as some specifics about each school.
Recommendations: I would strongly suggest approaching your recommenders soon. You want to give them at least 2 months to work on the recs (especially when they are doing more than one). For an Oct 13 deadline, that puts you at mid-August. But also take into account that you will probably want to have one meeting to break the news that you are leaving and then another a couple of weeks later to discuss your profile, goals, etc. to be included in the recommendations. (Definitely try to do it in two sessions, your supervisor may need a little time to let it sink in - at least mine will)