HP, which is now well practiced in programs like these thanks to three prior recalls, is providing free replacement batteries to those with affected machines.

After being plugged in for somewhere between 5 to 10 minutes I heard a sizzling sound. I looked down on the iPod just in time to see it explode open and start shooting sparks and spewing smoke. I managed to unhook the iPod from my computer’s USB port immediately. I noticed that a small fire had started on the table I had the laptop and the iPod sitting on, and I managed to extinguish those flames quickly before any apparent damage could be done to my laptop. Unlike in other cases, I’ve read about, my iPod continued to spew smoke and spit sparks while throwing out some kind of sooty substance from the inside of the iPod for several minutes after removing the cable from the computer.”

– A Consumerist reader recounts his experiences with Apple’s iPod Flamo

What an ugly week for Apple. Voice and data reception issues plaguing iPhone 3G, MobileMe still not up to company standards and now reports of sparking iPod Nanos. Japan’s Ministry of Economy, Trade and Industry (METI) is investigating a possible battery defect in Apple’s older iPod Nano music players after receiving reports of minor fires caused by overheating devices. “There have been multiple cases of overheating and fire damage, in particular during recharging, so please use caution,” METI said in a statement on its Web site.

METI is working with Apple Japan to diagnose the problem, which is said to affect only Nanos sold in Japan between Sept. 2005 and Sept. 2006, although there have been reports of similar incidents in the states.

Another tough break for Apple (AAPL), which just can’t seem to shake this negative news cycle.

UPDATE: Apple just issued the following statement:

Apple today responded to statements reported by Japan’s METI regarding batteries in the first-generation iPod nanos. Apple has determined that in very rare cases, batteries in first-generation iPod nanos sold between Sept. 2005 and Dec. 2006 can overheat, causing failure and deformation of the iPod nano. Apple has received very few reports of such incidents (less than 0.001 percent of first-generation iPod nano units), which have been traced back to a single battery supplier. There have been no reports of serious injuries or property damage, and no reports of incidents for any other iPod nano model.

Any first-generation iPod nano customers who have experienced their battery overheating should contact AppleCare for a replacement. Any other customers who have concerns about their first-generation iPod nano battery should also contact AppleCare.