SSH login without having to specify password each time

The following procedure works for OpenSSH_5.2p1, OpenSSL 0.9.8k-fips 25 Mar 2009. To check version of your ssh use $ssh -V. In case you have version other than this, please refer $man ssh and check which file permissions should be applied to Files (e.g. permissions of ~/.ssh/authorized_keys should be 640 otherwise ssh will ignore the file).

$:ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/swapnil/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/swapnil/.ssh/id_rsa.
Your public key has been saved in /home/swapnil/.ssh/id_rsa.pub.
The key fingerprint is:
67:50:53:ef:84:67:69:38:87:8a:03:14:fd:8b:df:68 swapnil@localhost.localdomain
The key's randomart image is:
+--[ RSA 2048]----+
| oo o.. |
| . .. . = . |
| . .. = O |
| . o.. O |
| S.+. . |
| .+. |
| . o |
| E . |
| . |
+-----------------+

Comment: Enter passphrase (empty for no passphrase): here simply enter a return key

Step 2:
$:cat .ssh/id_rsa.pub | ssh localhost 'cat >> .ssh/authorized_keys'
swapnil@localhost's password: 

Step 3:
$:chmod 600 ~/.ssh/authorized_keys  

Step 4: 
$:ssh localhostLast login: Fri May 21 16:06:34 2010 from localhost