Hey everybody,
Me and my friend are planning to visit Madrid and Barcelona in June and were just wondering how long we should stay in each city...we've been looking for hostals now but are not sure how many nights to stay... we want to visit all the main historical and architectural sites and basically get the most out of our trip...any ideas?

Muggles, I think most of the people on this board would reply to your question with : "forever".
Madrid and Barcelona are very different and for the average non - spainophile (?) a week in each city would probably be enough but then again, I could spend a week just visiting the Prado in Madrid and still not feel I'd "done" it.
However long you stay, you'd need to get out of the cities to really experience Spain. It all boils down, I guess, to why you're going in the first place and what kinds of things you like to do. How much time do you have?

The beauty of Madrid is the veritable plethora of side trips that break up the "big city" experience. There are a million things to do in town, but spending a week in Madrid with two days' worth of side trips to Segovia and Toledo should give you a great introduction to the capital. I'll leave the Catalán suggestions to someone who has a little more hands-on info...enjoy your trip!