LEFT and LIKE Alternatives on Windows Phone

Non-VB-specific methods are generally recommended anyways since they're generally the same across all .NET languages.

To get the left part of a string:

' Get left two letters
Dim start As Integer = 0
Dim length As Integer = 2
Dim Beginning As String = ("Some Text").Substring(start, length)

As for the "Like" operator, I've never used it but it seems to me that regular expressions would be a good substitute, if you're willing to learn it (not difficult).

Dim regexMatch As Boolean = Regex.IsMatch("Some Text", "^S.*")

The dot matches any character, and the asterisk modifies the dot to match zero or more any-characters (i.e. ".*" in regex behaves just like "*" in your code). The ^ matches the start of the string.

I also stumbled onto this article taking a different approach.