For a good insight into what the Bible says about the lie of homosexuality, go here (included is discussion about your Bible passages):
http://books.google.com/books?id=0uqFy8HBAXsC&pg=RA1-PT33&lpg=RA1-PT33&dq=meaning:++For+even+their+women+exchanged+the+natural+use+for+what+is+against+nature.&source=bl&ots=SWSL27whHa&sig=jLRk2C7QDeDpOQufSXDbU311YIU&hl=en&sa=X&ei=DNO3Us_3DIiCogTK34LgAg&ved=0CDgQ6AEwAg#v=onepage&q=meaning%3A%20%20For%20even%20their%20women%20exchanged%20the%20natural%20use%20for%20what%20is%20against%20nature.&f=false
Take a look at what I said (to someone else) in Post #25 ...