You can compare specs using gsmarena.com

I wouldnt really try and compare them. If you need desktop utility on your phone the n900 is in its own class as a phone

Where the iphone excels is commercial apps. Amazing screen. Slick OS that doesnt rely on terminal to work. Superb product development and support. Great accessories. loads of apps -quarter of a million to date. Super slim and sexy device. Better battery life. Other things too but its a good start.