The iPod touch has grounding problems. The unit grounds everywhere, so check you board and lcd ground strap, the copper ribbon, and see what happens. The 2nd gen lcd's are finnicky. if needed, remove and reinstall the LCD.
Your iPhone is only made for use with an iPhone Headphones which if compared to a Standard Headphone jack are different. Use the original headphones and plug them into your H/P jack and unplug. This is a common problem only caused by use of standard headphones. The iPhone H/P jack has 3 sections, left, right and mic. You will see on the jack 3 sections. If you are going to use a regular headphones. you need an adapter.