[Nero_3D]

First this wont work

pawn Code:

new Names[] = {"Michael", "John", "Katey", "Richard", "Robbin"};

because you create an array for arrays also you need two dimensions not one

pawn Code:

new Names[][] =
{ //just made the brace around the names to see better that they are arrays too
    {"Michael"},
    {"John"},
    {"Katey"},
    {"Richard"},
    {"Robbin"}
};

Than to your random problem

pawn Code:

new string[128];
format(string, sizeof(string), "%s says hello to you!", Names[random(sizeof(Names))]);
SendClientMessage(playerid, 0xFFFFFFAA, string);
//we get the array size with sizeof(Names) - the size of the first dimension is 5
//so we do indirect random(5); which will return a number from -1 till 5 (0, 1, 2, 3 or 4)
//so when random as example return 3 it will be Names[3] and that is "Richard"