Absolutely, without a doubt, take an LSAT class (Powerscore seems to be pretty good). I did not, and boy do I regret it. With your UGPA, you will need to crush the LSAT for Chicago and Virginia. You can also register on LSAC. There is lots of info there about the process as well. Good luck, and congratulations on having the courage to re-evaluate your career path!
I would also consider Northwestern if I were you. They like older applicants who have had significant work experience, and you may find that this will mitigate your fairly low GPA in their eyes. They would probably be your best bet in the T14 unless you get a 175+ on the LSAT.
The current (Fall 2008) cycle is basically done, so your target enrollment would be sometime in 2009 -- probably fall, though spring or summer entry is an option at some places (but not UVa, probably not UC).What you can do now: First, I would suggest getting the LSAT info book put out by the Law School Admissions Council (lsac.org). You can get this from a college pre-law office, a law school, or probably from LSAC itself. There is a full-length practice test in there. I suggest timing yourself and taking this test under actual conditions, to give you a benchmark of where you stand. Basically, if you kick ass (like 170+), you can relax and just do a little prep work. If you do well (I dunno, maybe 160+), then try to prep on your own or maybe take a class to make up any shortcomings; you'll likely need a middle-170s score to get into Chicago or UVa with your GPA. If you make below 160, then definitely take a class, or possibly re-evaluate your options; if you're scoring in the low 150s or lower, you may be able to improve your score, but it will not be easy to make up enough points to get into the top tier that you're targeting.Depending on if/when you do a prep course, you can take the LSAT either in June or October (dates: http://lsac.org/LSAT/test-dates-deadlines.asp). You probably will be applying during this fall, but you could also take the December test if you didn't do as well as you hoped in June/Oct. I would advise the June LSAT (if you're not doing a course) since it gives you a) a good idea of where you stand BEFORE you even start applying; and b) two chances to re-take if you mess up.You'll also need to sign up for LSDAS, which is a service of LSAC that compiles transcripts (from every college you ever attended) and recommendations (you'll need two, preferably from professors you had in school, but an employer would probably be OK given your personal situation) to send to schools. (You have to send everything to LSDAS, which then puts them in a format the law schools understand.) You can fill out your applications on their site, also, starting around September.Hope this helps. Good luck!
Yeah, I would second the above response. For better or worse, the LSAT is really the key to the whole process. I would suggest doing independent study and figuring out what sort of LSAT score you need to get to attend the schools that you would like to. Understand that most people do poorly on the test at first, and that you can improve your score. Rather than taking the test as a part of your application cycle, I would recommend getting your score where you'd like it first and then beginning the process. There are a number of decent books on the application process, including "Law School Confidential" and "How to Get Into Law School" by Susan Estrich. They explain a lot of the basic information, including ideal times to take the LSAT and apply to schools.