Regular Expression

Need to find more then one value ( with a formated string .. Ex. {:Test:}) in a sting using RegEx.

//Step A
using System.Text.RegularExpressions;
//Step B
string input = "It contains lot of lines with this {:firstname:} and ({:lastname:})";
MatchCollection m = Regex.Matches(input, "{:[A-Za-z0-9_]+:}");
//Step C
Loop through the MatchCollection and find the each value