Answer to: Any ideas of the manufacture of iPhone speakerWell I don't know who supplies the original, but here is a 3rd party solution: http://www.dealsniper.com/home/iphone-3g-3gs/repair-parts/2292-speaker-replacement-for-iphone-2g-3g-3gs.html?src=gb_us¤cy=USD
Answer to: Why does a message appear saying 'write error' when taking a picture?There could be a few reasons. It could be a bad memory card, first try formatting the card (this would erase any images but if there are none on there you wouldn't need to worry about it). If that doesn't work maybe try another card. The contacts between the camera and the memory card could be bad or dirty. Take out the card and make sure the area where the metal contacts on the card touch the contacts the camera are clean and free of debris. Also, make sure the card is in properly. If none of those work then it is most likely a problem with the camera itself, in that case you would probably have to take it to be serviced.
Answer to: The section to accept the sim card is damagedWell, on all iPhones the SIM card goes directly into the logic board. This is technically replaceable, but it is so expensive and difficult that you might be better off buying a new phone. A 16GB logic board for the original iPhone is $300 if you order from this site, a new 16GB iPhone 4 is $200 with contract. If you do decide to replace your own board, more power to you, just make sure that you get the correct model. Also, this will replace your phone's internal storage, so make sure you back everything up on your computer before replacing the part. After you replace it you will have an phone with nothing on it, as if it were new. You can then sync all of your apps and music, etc back to it from iTunes.