When it comes to estimate the cost of any device, none is better and faster than iSuppli.  No hard guess what they are up right now, obviously it is iPhone 4, the phone that sold 1.7 millions unit in 3 days.

According to iSuppli, the total coat of bill of materials (BOM) or parts in layman language is USD187.51 for iPhone 4 16GB. That’s excluded the manufacturing cost though.  For comparison, iPhone 4 16GB is sold at USD199 with 2 years contract, but Apple does have a cut from the data and voice revenue from the telco.

Read more of the estimation from the source link below.

source : isuppli