I graduated from Hopkins in 06' and took a job at Fried Frank in NYC. To get a positition, most of the top 50 firms listed by vault.com have very competitive application processes for hiring legal assistants. Almost all of them have two year programs oriented towards the law school bound individual. The application process starts in the Fall to early January. You can visit any of the firms websites to get more info on their hiring process legal assistant applicants.
If you are at a top 20-30 firm, be prepared to do 20-30+ hours a week in O/T. This will give you a sense of what working at a big firm is like hour wise. During trials we can work up to 100 hours in a week or travel out of state. This is not in any means a glamorous job, although all the perks are great: car rides home, meals after 8PM, subsidized gym memberships etc...be prepared to stretch your endurance to manage long hours and high stressed environments.
Starting salary is usually 36-40k at any of the big firms in NYC/DC/LA. I grossed well over 70K my first year because of all the O/T I did. Note, I also did not have a life. There are a lot of ambitious legal assistants looking to get a partner recommendation letters, this is rare but doable if you prove yourself. Even when your in at a top firm, you have to work hard to impress someone enough to write you a rec. letter.