wa alaikum assalam,

It's definately a difficult thing to figure out. Some websites base their rulings on the precidents of madhabs, schools of thought, that developed over the centuries. Others base their rulings soley on the Qur'an and the sunnah of the Prophet (saws), without taking into account how the madhabs have interpreted these sources. The posters on this website tend towards the later group.

As a newbie, I'd recommend IslamOnline, because it finds a balance between the different sources. Oftentimes, their rulings will present the different points of view.