Here's a good thread compiled about all things recruitment as discussed on GC last summer
Here is a list of GC'ers willing to write recommendations AND/OR assist you with finding a recommender in your area to write you a rec:
http://forums.greekchat.com/gcforums...threadid=48462
Recommendations are always helpful. In some sororities, recs carry more weight than in others, and it doesn't hurt to be prepared! If you don't know your recommenders personally-- an alumna through your hometown's Alumnae Panhellenic is assisting you, a GC'er or friend-of-a-friend, than one rec per sorority is sufficient.
I don't know about your university Greek System, but I do advise you to call the Office of Greek Life (or if there isn't one, than to call the Office of Student Activities) to request figures on the number of juniors placed in recruitment last year out of those rushing, as well as freshman, sophs, and seniors.
Ask them their advice for a junior transfer coming into recruitment, what to expect, wear and general advice on Greek Life at your new university. Picking up the phone and speaking one-on-one guarantees a more intimate experience and perspective than cold emailing.
Good luck with recruitment and call the university today! You may not have as competitive a recruitment as an underclassman, but then again, depending on you and your campus, you might have a very competitive recruitment. Regardless of what year you are in school, remember that recruitment is a weeklong interview, and a subjective process of mutual selection by both you and the sororities. They're looking for members that mesh well with their chapter culture, and you're looking for a place you will fit in well with.
Plan to get involved with a club on campus regardless of whether you join a sorority and remember that being cut from chapters in recruitment is part of the recruitment process (it will be the same way once you are out of school-- not every employer you interview with will offer you a job, no matter how great you are!). Spend this time prior to the fall getting good grades, doing community service, meeting people, securing recommendations, going through your wardrobe to select appropriate attire, practicing interview-type questions/responses, researching the chapters at your school and getting acclimated to your new university.