O.k., here we enter into the error of the "SOUNDEX"!  Our U.S. Federal Census records have increased dramatically along with the population.  There are so many people now that it made a lot of sense to instate a Soundex (Index of the U.S. Federal Census).

Here are the directions for how to calculate your "Soundex Code" for you last name.  It is a little tricky but you'll get the hang of it. 

Basic Soundex Coding Rule: (Thanks to GedPage for the info.) 
Every soundex code consists of a letter and three numbers, such as W-252. The letter is always the first letter of the surname. The numbers are assigned to the remaining letters of the surname according to the soundex guide shown below. Zeroes are added at the end if necessary to produce a four-character code. Additional letters are disregarded.
 
1) B,P,F,V
2) C,S,K,G,J,Q,X,Z
3) D,T
4) L
5) M,N
6) R

Examples:
Washington is coded W-252 (W, 2 for the S, 5 for the N, 2 for the G, remaining letters disregarded).
Lee is coded L-000 (L, 000 added). Additional Soundex Coding Rules

Names With Double Letters
If the surname has any double letters, they should be treated as one letter. For example:
Gutierrez is coded G-362 (G, 3 for the T, 6 for the first R, second R ignored, 2 for the Z).

Names with Letters Side-by-Side that have the Same Soundex Code Number
If the surname has different letters side-by-side that have the same number in the soundex coding guide, they should be treated as one letter. Examples:
Pfister is coded as P-236 (P, F ignored, 2 for the S, 3 for the T, 6 for the R).
Jackson is coded as J-250 (J, 2 for the C, K ignored, S ignored, 5 for the N, 0 added).
Tymczak is coded as T-522 (T, 5 for the M, 2 for the C, Z ignored, 2 for the K). Since the vowel "A" separates the Z and K, the K is coded.

Names with Prefixes
If a surname has a prefix, such as Van, Con, De, Di, La, or Le, code both with and without the prefix because the surname might be listed under either code. Note, however, that Mc and Mac are not considered prefixes.

For example, VanDeusen might be coded two ways:
V-532 (V, 5 for N, 3 for D, 2 for S)
or
D-250 (D, 2 for the S, 5 for the N, 0 added).

Consonant Separators
If a vowel (A, E, I, O, U) separates two consonants that have the same soundex code, the consonant to the right of the vowel is coded. Example:
Tymczak is coded as T-522 (T, 5 for the M, 2 for the C, Z ignored (see "Side-by-Side" rule above), 2 for the K). Since the vowel "A" separates the Z and K, the K is coded.
If "H" or "W" separate two consonants that have the same soundex code, the consonant to the right of the vowel is not coded. Example:
Ashcraft is coded A-261 (A, 2 for the S, C ignored, 6 for the R, 1 for the F). It is not coded A-226.

If this is way to hard for you to calculate on your own, like it is for most of us, you can go to a "Soundex Calculator" online at:

http://www.frontiernet.net/~rjacob/soundex.htm