553
Given an array you can use the Array.ConvertAll method:
int[] myInts = Array.ConvertAll(arr, s => int.Parse(s));
Thanks to Marc Gravell for pointing out that the lambda can be omitted, yielding a shorter version shown below:
int[] myInts = Array.ConvertAll(arr, int.Parse);
A LINQ solution is similar, except you would need the extra ToArray call to get an array:
int[] myInts = arr.Select(int.Parse).ToArray();