Gretta,
Plug adapter - changes the plug of any appliance from US to UK. It just sticks on the end of the cord so that you can stick it in the wall. easy peasy. Best used when dealing with dual voltage appliances (like some hair dryers and computers etc).
power converter - changes the voltage from US to UK standards or vice versa. This is for things that dont convert the power internally like fridges, microwaves etc. The bigger the appliance the bigger converter you need. converters for small appliances like hair dryers are small and pretty inexpensive I think.
check apple's website to see if the IPod is dual voltage. If it is, you wont need to worry about a power converter. Just a plug adapter. If it isnt dual voltage you'll need a power converter to charge it up if you cant put batteries in it. I would IMAGINE, though this is just a guess, that the IPod will be dual voltage because of its nature - take it with you wherever you go, use it during travel etc.
your lamps - all you need to do with lamps is change the cord and lightbulb socket. Sometimes changing the light bulb socket isnt even necessary, depending on if you can get the right kind of bulbs where youre going. might want to take the kind of light bulbs you need for your lamps with you on your trip and take a stroll through Ikea to see if you can match them up. B&Q is right next to Ikea and they have a good selection of blubs too. So do the supermarkets. That'll proove if you need to change the bulb sockets on your lamps as well as the cord.
A lot of removals companies can either make the change for you, or point you in the direction of someone who can. Call Sterling International Relocations - they deal with a lot of company transfer moves and do all sorts of things for you including scouting for appartments, renting furniture for your appartment so its ready to move into when you arrive, right down to changing your lamps over for you and supplying you with power converters.
Hope that helps!
Sarah