I recently have been looking around for a wall charger to charge my Zune at night so i don't have to keep my comp on all night, so i went to Fry's i got an adapter that goes from your wall outlet to a USB connector, that works great and for 12 bucks i thought it wasn't too bad. but of course 4 days after i did this i saw a post on
www.I-Hacked.com about a DIY Ipod shuffle charger, that converts a normal DC adapter to +5v DC... the same as a computer's USB port.
(some of the following i cannot take credit for, as it was copied from I-hacked user's:
http://www.microhaxo.com. how ever i have modified it so it will work for a Zune or any other USB dependent device)
Parts List
1 Female Type A USB connector
1 +5VDC Voltage Regulator (RadioShack #276-1770)
1 Project enclosure (RadioShack #270-1801) or similar
1 General purpose PC Board (RadioShack #276-149) optional
1 AC/DC adapter at least 8v but no more than 12v (find this around the house)
1 15k Resistor
Tools:
DMM (Digital MultiMeter) or Equivalent – a must have
Soldering Iron
Solder
Wire (28 gauge) – might need it
Screwdriver
Flux (not required)
Electrical tape or shrink
Warning:
I have not tested this yet as i just found out about it, but it should work if done right. If you would like to attempt this, CHECK YOUR VOLTAGE FIRST! and make sure its at 5v and maybe test it on an old junk Ipod (jk) It is not my fault if you follow my directions and it doesn’t work, you should always use your multi-meter and double, triple, quadruple check things, but it is not my fault if you screw up anything! if you have doubts DO NOT DO THIS!!!
Assembly (The charger Bit)

First you want to clear an nice bright area to work in, then lay out all of your parts. Slice the female USB cable and peel away any foil / casing that is around it so that the wires are exposed; leave a little extra wire in case of accidents. Now strip the USB wires and twist the green and white together at the ends, and then tin them (Makes it easier to solder). Now individually tin the ground and the Power tips (not necessary but good idea), Follow the diagram as shown and you will have a working AC/DC Zune Charger. Make sure to check and see if the regulator is giving out 5v by checking with your multi-meter.
Here is the AC to DC charger for the wall outlet the author used for the shuffle:

Now to get it into the case you need to cut the actual PC board to fit, the author cut his/hers so one of the corners could be screwed into the box, keeps it secure. You will also have to cut a small notch in the project case for the USB to plug into, he/she used a jewelry saw they had laying around you could use a dremel or I suppose some clippers if you want to be messy. DON’T forget to get a little hole on the opposite side for the POWER CORD to come out of! Use the Electrical tape to cover any exposed wires after soldering to the pc board and or the regulator, you don’t want any bad things to happen when charging

. Use some leftover electrical tape to secure the female USB connector so it doesn’t get pushed in, They also used some Popsicle / stir sticks propped against the back of the case and the USB to hold it in place. Remember to check all connections with multimeter, you are looking for 5v.
Arther's finished product: (i fixed the sticker)

* to be on the safe side you could add a 15k resistor to each the green and white wires, and you could add 2 47uF capacitors to the input and output of the regulator, just to be super safe.
if you would like to see the original article please go to:
http://www.i-hacked.com/content/view/245/90/i will probably make mine Friday or over the weekend, when i do i will take pictures and all that jazz, and tell you if my works or not, so if you want to wait till then to see the one for the Zune that works for sure, it will be up by sunday.
hope this helps some DIYers