These are probably the simplest of random password generators you can come up with in C# or VB.Net. The T-Sql is a little bit fancier, with actually two different random strings being procuded from two choices of "character arrays". Its pretty easy to see whats going on there and pick and choose which way you would want to use. I also programmatically loaded the alphanumeric characters in T-Sql rather than typing them in. Also, the T-Sql isn't in UDF format or SP format, so you will have to make a few minor changes (basically just creating an OUTPUT parameter for the @password variable) to make it work outside of Query Analyzer.
Update:Changed the C# code per Gerd's comment.

Update: Get the lastest and greatest Random Password Generator in T-Sql for Sql Server here.

C#

using System;
using System.Text;

public class PasswordGenerator
{
    private char[] characterArray;
    private Int32 passwordLength = 10;
    Random randNum = new Random();

    public PasswordGenerator()
    {
        characterArray = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".ToCharArray();
    }

    private char GetRandomCharacter()
    {
        return this.characterArray[(int)((this.characterArray.GetUpperBound(0) + 1) * randNum.NextDouble() )];
    }

    public string Generate()
    {
        StringBuilder sb = new StringBuilder();
        sb.Capacity = passwordLength;
        for (int count = 0; count <= passwordLength - 1; count++) 
        {
            sb.Append(GetRandomCharacter());
        }
        if ((sb != null)) 
        {
            return sb.ToString();
        }
        return string.Empty;
    }
}

VB.Net

Imports System
Imports System.Text

Public Class PasswordGenerator

    Private characterArray() As Char

    Private passwordLength As Int32 = 10

    Public Sub New()
        characterArray = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".ToCharArray
    End Sub

    Private Function GetRandomCharacter() As Char
        Randomize()
        Dim location As Int32 = -1
        While Not (location >= 0 AndAlso location <= Me.characterArray.GetUpperBound(0))
            location = Convert.ToInt32(Me.characterArray.GetUpperBound(0) * Rnd() + 1)
        End While

        Return Me.characterArray(location)
    End Function

    Public Function Generate() As String

        Dim count As Int32
        Dim sb As New StringBuilder

        sb.Capacity = passwordLength

        For count = 0 To passwordLength - 1
            sb.Append(GetRandomCharacter())
        Next count

        If (Not sb Is Nothing) Then

            Return sb.ToString
        End If

        Return String.Empty

    End Function

End Class

T-Sql

declare @string varchar(10)
declare @string2 varchar(10)
declare @choices varchar(100)
declare @count int

set @choices = ''

-- load up numbers 0 - 9
set @count = 48
while @count <=57
begin
    set @choices = @choices + Cast(CHAR(@count) as char(1))
    set @count = @count + 1
end

-- load up uppercase letters A - Z
set @count = 65
while @count <=90
begin
    set @choices = @choices + Cast(CHAR(@count) as char(1))
    set @count = @count + 1
end

-- load up lowercase letters a - z
set @count = 97
while @count <=122
begin
    set @choices = @choices + Cast(CHAR(@count) as char(1))
    set @count = @count + 1
end

declare @whatever varchar(100)
set @whatever = 'JackAndJillWentUpTheHillToFetchAPailOfH20'
set @whatever = @whatever + 'PittsburghWinsTheSuperBowl'

set @count = 0
set @string = ''
set @string2 = ''

while @count <= 10
begin
    set @string = @string + SUBSTRING(@choices,CAST(ABS(CHECKSUM(NEWID()))*RAND(@count) as int)%LEN(@choices)+1,1)
    set @string2 = @string2 + SUBSTRING(@whatever,CAST(ABS(CHECKSUM(NEWID()))*RAND(@count) as int)%LEN(@whatever)+1,1)
    set @count = @count + 1
end
print @string
print @string2

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Posted 01-13-2005 10:21 AM by Raymond Lewallen