MySQL is a TCP protocol running on port 3306 by defauly, hence there is nothing special beyond ensure that you have enabled binding to a public IP address in the /etc/my.cnf
file;
port = 3306
bind-address = 0.0.0.0
On the client you would need to install the jdbc drivers for MySQL;
For windows XP they can be downloaded from here;
http://dev.mysql.com/downloads/connector/j/
For ubuntu, there are package version in the repository;
# aptitude search mysql | grep JDBC
p libmysql-java - Java database (JDBC) driver for MySQL
You can use any client, mysql provide a workbence tools product;
http://dev.mysql.com/downloads/workbench/5.2.html
or you can use Libreoffice and their database connection to view the tables;
http://www.libreoffice.org/features/base/
Or use a scripting language like php;
http://php.net/manual/en/book.mysql.php
or even just the command line client;
$ mysql -h192.168.2.5 -uuserXXX -e "show databases;"
+--------------------+
| Database |
+--------------------+
| information_schema |
| badger1 |
| cacti |