I'm a Mandarin learner myself, and Pleco is a life saver. If you can find an app where you type or draw the word and it gives you a translation it's incredibly helpful. Have you learned any languages already?
If you really get serious about learning Korean you'll quickly find that you need more than an "app" to get there. As others have said, Rosetta is a great resource. Dig through the bookstore and find several books. Toss one in the bathroom, and others here or there where you can pick them up for 5-10min and you'll quickly see a level of familiarity falling in place.
Get a Korean girlfriend or, if the wife has a problem with that... go make friends with some old man who has time on his hands. This really is important because there's a real difference between books and reality. I taught myself Mandarin Chinese years ago and, as I was getting some of the basic grasp on it, it didn't take long for people to start telling me "Yes, that is the proper way to say it, but this... is what we would normally say."
Once you get the basics, find one or two things everyday related to your job, relevant technical terminology etc., and take those home with you to add to the study list.
Good luck with it.
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Speed doesn't kill. Sudden stops, brick walls, and old ladies in Buicks do.