Grant access to a table to all users
What I am about to propose would be considered by many to be a hack, but will get you what you want.
STEP 01 : Create a special database called specialdata
CREATE DATABASE specialdata;

STEP 02 : As root@localhost, place the table you want into the specialdata database
CREATE TABLE specialdata.specialtable LIKE mydb.mytb;
INSERT INTO specialdata.specialtable SELECT * FROM mydb.mytb;

STEP 03 : Create anonymous user access to the specialdata database with the needed grants
INSERT INTO mysql.db
SET host='%',user='',db='specialdata',
Select_priv='Y',Insert_priv='Y',Update_priv='Y',Delete_priv='Y';
FLUSH PRIVILEGES;

STEP 04 : There is no STEP 04
Every user should have access to any table in specialdata
Give it a Try !!!