I am interested in the development and use of applied linguistic methodology (e.g. corpus linguistics) in language education contexts as well as in non-language education related areas, e.g. health and disaster communication. It is worth bearing in mind when doing your MA that applied linguistics is expansive and expanding in terms of the domains in which it applies. For some examples, you can look at the past talks in the seminar series on corpus linguistics I run with Clyde (shameless plug).
And of course look out for emails about upcoming ones! If you are not already aware, a corpus is simply a large collection of texts, which can be analysed using various types of software. It is, for instance, a great way of ascertaining if a particular language form (e.g. a phrasal verb) is appropriate for a given context. In this sense, Google can act as a massive corpus – if a rather untamed and unruly one. If you want to explore a systematically constructed and structured corpus (e.g. divided into written and spoken genres), take a look at the British national corpus. This is one of several online interfaces you can use (e.g. to look up how or whether a particular type of language is used in a given genre or register). Take a look at the Phrases in English website.
In terms of SLA, I think Viv Cook is fantastic at translating the implications of SLA theory and research for teaching practitioners. He has a website and blog including lots of past articles, musing and explanations.