How far apart are the houses and are ther lots of solid brick walls in the way ? Unless there is a direct line of sight between the wireless transmitter and receiver you will probably have problems.
You would need a wireless router with inbuilt ADSL modem for the house with the DSL link and then simply a wireless card for the other. Wireless ADSL routers cost about $75 so not much to lose by trying it out. You can pick up a bundle at Newegg (router and card) for $99Newegg