Strongly related to the term "fixins", "fixin' to" is a United States Southernism. If you say that you are fixin' to do something, it means that you're preparing to do it or will be doing it soon. For example, one might say, "I'm fixin' to go to the store. Ya'll wanna come?" This phrase sometimes annoys those from north of the Ohio River -- my parents (natives of Maine and Illinois) certainly didn't seem too overjoyed when I dragged it home from kindergarten. (If I remember correctly, it went in the pile of "words to quickly eradicate from my vocabulary" with ain't and ya'll)