PHP-MYSQL Error: Can't connect to MySQL socket. Can someone help me out please?

I am using Fedora Core 4. As I was unable to use PHP or MySQL together, 
I uninstalled both of them and installed again using the following commands:

yum install mysql

And then

apt-get install php php-devel php-gd php-imap php-ldap php-mysql 
php-odbc php-pear php-xml php-xmlrpc curl curl-devel perl-libwww-perl 
ImageMagick

And then started the mysql server.

I am able to connect to the server from the console my typing

mysql -h <hostname> -u root -p <mypass>

However, when I try to connect to mysql through PHP I get the following 
errors:

PHP Warning:  mysql_query(): Can't connect to local MySQL server through 
socket '/var/lib/mysql/mysql.sock' (2) in 
/export/home/rahul/may/sample.php on line 5
PHP Warning:  mysql_query(): A link to the server could not be 
established in /export/home/rahul/may/sample.php on line 5
Can't connect to local MySQL server through socket 
'/var/lib/mysql/mysql.sock' (2)

Can someone please help me out?