I was a "Summer Law Clerk" last summer as a 1L at a mid-size firm. I think that's just the term they chose to go with (there were no "summer associates" there). They paid me well, they "groomed" and trained me, and they took me out to lunch/events (games, dinners, cruises, etc.) pretty much 4 days a week.
It's probably different though if a firm has both "Law Clerks" and "Summer Associates". From what I remember reading about it, I think the work for law clerks is more restricted to a specific practice. i.e. they hire you only to do real estate crap work, or only for document review in litigation, etc. More like a paralegal than an associate it sounds like...JD might not even be required.
Good luck -- it's better than nothing!