I had this on one of my wp blogs and never gave it any thought nor thought about putting it on my other blogs.

But I got an email from my host company that there is currently a distributed attack against WordPress logins globally that is trying to hack WordPress installations by brute forcing the logins "wp-login.php" file.

So of course I checked my original .htaccess file on the blog and it was already set up.
And I put it on my other blogs in the .htaccess file.

Just add this to your .htaccess file, or create a .htaccess if you don't have one.

<Files ~ "^wp-login.php">
Order deny,allow
Deny from all

Allow from x.x.x.x

Where the x.x.x.x is your ip address.

That way, only you from your ip address can login.