Wow, what a disgruntled person it is that started this thread. I graduated relatively recently (2013) with my MLS and within six months was full-time employed in a library job, so it's untrue that there aren't any jobs and libraries are dying. I don't think libraries are dying - I actually think they're at the start of a renaissance/rebirth, and the librarians I know are very passionate about what we do.
Here is my advice to people considering an MLS/MLIS/MIS/whatever your particular program calls it.
1. Know why you want to go to library school. This should go for any graduate program, really, but I'd say that at least half of the people I went to school with didn't have any idea why they were there beyond "I like books! I'll get my MLS and then I can be around books all the time!" Not one of those people is actually employed in a library job today.
The people who could give me a) the specific job they wanted to do when they graduated, the reason they wanted to do that, and c) a realistic perspective on how long it would take and how flexible they would have to be about geography are the people who are employed in libraries. They're the people who are actually passionate about the values and ethics behind libraries, as opposed to the people who dithered and took classes in anything and everything and hoped it would show them as being "well-rounded." Yes, I have friends who wanted to be archivists who are now employed as archivists. It IS possible, but you have to work your ass off and be PASSIONATE about what you're doing instead of seeing it as something to do with an English/history/philosophy undergraduate degree.
2. Work hard to get into an accredited, good program. Yes, there are good programs and bad programs. No, not everyone gets into the good programs. If you get into a good program and play your networking cards right, it will open a LOT more doors for you than going to any old online school. You want to be an archivist? Great, join the student chapter of Society of American Archivists, run for office, and get stuff done while you're there. Go to student socials, no matter how stupid or lame, because knowing as many people as possible in the field can only help you down the line. Treat the two years you'll spend in a program seriously and don't just blow it off as a bunch of "grade school BS," because if you truly want to work in libraries, it's not.
3. Be active in the professional community! I cannot stress how important this is, even when you're in school. Join your state chapter of ALA as well as the national one - you'll make better connections there. Figure out who you need to know and get to know them. Even if you think social media is stupid, take part in conversations on Twitter and Tumblr - a lot of professional conversation takes place there for librarians of all disciplines. Being a librarian is every bit as much about liking people as it is about liking books, and all the people I know who are the most successful at it are comfortable in social situations and enjoy talking to people.
4. Don't take on an unreasonable amount of debt to go to graduate school. You probably already know that librarianship is not a six-figure-a-year profession. THERE IS NOTHING WRONG WITH THIS, despite what some disillusioned curmudgeons around here will tell you. I'm way happier making as a children's librarian than I ever was in any job I had before I came to library school. But it does mean you should carefully consider your financial aid package and work your butt off while you're in school to get any scholarships that could apply to you.
5. Most importantly, do not listen to embittered cranks like Shep, who are going to do anything and everything to drag you down and make you feel like librarianship is the worst field in the world to go into. It is not for everybody and not everyone I knew in school is still active in the profession - but the majority of those people didn't go into the program knowing what they wanted to get out of it. If you know what you want to do and are willing to work HARD for it, and if you can be happy without a six-figure salary, librarianship is a really rewarding career. But in the current hiring climate, it is critical to know as many people as possible and outshine the competition in every way. That includes having a true passion for what you're about to do - that shows loud and clear in job interviews, now that I'm sitting on the other side of the desk.
Good luck whatever you decide to do!