First there was Creative's Zen and soon there'll be Microsoft's Zune, and no doubt there'll be many more – one of which might actually succeed in "killing" Apple's iPod.

Sony tried and failed with numerous versions of its Walkman digital-music player, but its portable PlayStation game device (PSP) was yet another iPod killer that was better at video and could also play games better than Solitaire.

Well, it ain't – because it too appears to be withering in the dazzling light of the iPod. Sony has this week admitted that PSP shipments are well below expectations.

Sales this year were apparently always to be below 2005's levels, but they're actually falling much faster and sooner than initially anticipated.

The PSP was launched in Japan on Decemeber 12, 2004, and 3 million units were shipped by the end of March 2005. In the financial year from April 2005 shipments jumped to 14.1 million units as the machine went on sale in North America and Europe. For the current fiscal year, from April 2006, Sony initially said it expected shipments would decline to 12 million units, but this week revised that figure to 9 million units.

Apple sold nearly that number of iPods in July, August and Sepetmber of this year.

Of course much of the PSP's decline is down to Nintendo's DS, and its highly popular brain-training games. But it's kinda satisfying to see another much-vaunted killer tripped up and firing blanks.