I have these strips of leds (http://i1091.photobucket.com/albums/i398/ukmiya/IMG_372a5.jpg) wired up to the parkers (they are 12v), but after a couple of weeks some of the leds have died (the first ones in the row). Would a resistor fix this? And what sort, any 12v resistor, or would it need it need to be say 8ohms or 4ohms?

I have used led strips all around my car with no problems. I prefer using smds myself. Id assume they have resistors and they are just cheap and nasty leds. Possibly a cause of Voltage spikes, though Im only speculating from an Led noobs perspective :) Wouldnt hurt trying a 12v Linear reg.

No they just die, some led just do that, or could be a dry joint in the solder joint, and a resistor wouldnt do much.

I have used led strips all around my car with no problems. I prefer using smds myself. Id assume they have resistors and they are just cheap and nasty leds. Possibly a cause of Voltage spikes, though Im only speculating from an Led noobs perspective :) Wouldnt hurt trying a 12v Linear reg.
Do you run any of your led strips from the parker wires? And would this regulator (http://www.ebay.com.au/itm/New-1pc-DC-DC-Converter-Regulator-12V-to-5V-3A-15W-Car-Led-Display-Power-Supply-/200869620003?pt=AU_B_I_Electrical_Test_Equipment&hash=item2ec4c32923) be fine to use? I know the output is only 5v but that should still be more than enough for leds shouldn't it? Sparky feel free to chime in here :)

Probably just poor quality. That or waters gotten into them or something?

Do you run any of your led strips from the parker wires? And would this regulator (http://www.ebay.com.au/itm/New-1pc-DC-DC-Converter-Regulator-12V-to-5V-3A-15W-Car-Led-Display-Power-Supply-/200869620003?pt=AU_B_I_Electrical_Test_Equipment&hash=item2ec4c32923) be fine to use? I know the output is only 5v but that should still be more than enough for leds shouldn't it? Sparky feel free to chime in here :)

Running a 12v device on 5v will be effectively half and a bit of the expected voltage. The LEDs will be considerably duller and depending on the led might look funny (some of the bluey white ones go a funny colour when the volts drop)

Do you run any of your led strips from the parker wires? And would this regulator (http://www.ebay.com.au/itm/New-1pc-DC-DC-Converter-Regulator-12V-to-5V-3A-15W-Car-Led-Display-Power-Supply-/200869620003?pt=AU_B_I_Electrical_Test_Equipment&hash=item2ec4c32923) be fine to use? I know the output is only 5v but that should still be more than enough for leds shouldn't it? Sparky feel free to chime in here :)

I tend to think that wouldnt work, but I may be wrong...
I actually had the same lights as drls in my KR headlights. Never had a problem with them.
For you to have more than one go on you, its a wonder. Keep in mind... these are far from quality! So its too easy to blame that factor.