you can do it a couple of ways. the easiest (to me atleast) is just to take the string value, then return an array of the characters that make up the number. you can also create an array by doing bit manipulation.

Code:
public int[] GetDigits(int number) {
    string temp = number.ToString();
    int[] rtn = new int[temp.Length];
    for(int i = 0; i < rtn.Length; i++) {
        rtn[i] = int.Parse(temp[i]);
    }
    return rtn;
}