Well, go ask your neighbor! It actually is illegal (US, UK, Canada, AU and others) to connect to a network without the owners permission! It has a very high fine and even jail terms in some areas!
Some ISP's also have contract limits that prohibit sharing.
So just go ask your neighbor.
Routers are available for under $30.00 US these days!
Here's one for $28.99
http://www.geeks.com/details.asp?invtid=F5D7130&cat=NET&cpc=NETbsc
That is much less than the legal fees and fines you might get yourself into.
Also once you connect to your neighbors network -- well you are connected to HIS network and he has admin rights to run his network - (meaning he has access to YOUR machines and can actually watch your sent and received information!)
Here is a link to the laws and other good reasons NOT to STEAL wifi!
http://news.com.com/8301-10784_3-9722006-7.html
http://www.designnine.com/news/?q=node/423
http://www.dailynugget.com/2006/03/man_fined_250_for_wifi_piggybacking.php
http://www.newswireless.net/index.cfm/article/2317
and the LEGAL reasons
Wifi theft Laws
http://www.ncsl.org/programs/lis/cip/hacklaw.htm
N.Y. Penal Law § 156.00 to 156.50
§ 156.05 Unauthorized use of a computer.
A person is guilty of unauthorized use of a computer when he or she
knowingly uses, causes to be used, or accesses a computer, computer
service, or computer network without authorization.
Unauthorized use of a computer is a class A misdemeanor.