Is it possible to connect two wireless routers?

Is it possible to connect two wireless routers to expand a network wirelessly without any additional hardware? If so, can someone please send me instructions on how to do the same? Thanks.

It depends on the wireless routers and the distance of the link, you could buy one high powered unit from here, http://www.air802.com/indoor-acces. This is the highest powered(250mW) and most reliable unit I have used. I connect with my home network three laptops, two towers, Tivo (download movies), print server and Logitech internet radios for audio streaming all at the same time with very little degradation in service. This is a very reliable unit and it only costs $134 or $94 depending on the metal or plastic enclosure. I will be buying a second unit to extend the range for the pool area. Highly recommended, great security and configuration flexibility and high powered. They also sell outdoor high powered routers that are advertised with a 5 mile range.