enter value from form to database table

in my php page , ther is a form for ntering email , shown below ..
whenever a user enters email , i need to add tat to my database table 'log_table'.

<tr><td>email</td><td><input type="text" id="email" name="email" value=""/></td></tr>

to add to table , i used the foll , query

sql_query("INSERT INTO log_table (email) VALUES ('$_POST['email]')");

but it doesnt work.. pls give me a solution ..

What's ql_query() ?

I think the code was cut off, it's suppose to be this.

mysql_query("INSERT INTO log_table (email) VALUES ('$_POST['email]')");

make it simpler!

$email=$_POST['email'];
//do email validation here, remove any quotes
// from the email input or else expect sql injection attacks!

mysql_query("INSERT INTO log_table (email) VALUES ('$email')")