From what I understand, the fix may not be coming if it's related to the iPAQ 5000 series. The reason I say this is Linksys will mostly not devote any resources to solve an isilated issue thats make and model specific.
Again, HP will not devote resources that manufacturer and model specific in regards to a Linksys 802.11g router.
Also, I am not specifically familiar with the chip in the Linksys but if this chip is embedded firmware, this will mean replacing the chip with a version of 802.11g which is more standardlized and generically compatible.
If the iPAQ 5000 series is the only PocketPC with connection issues then I cannot see Linksys replacing this chip . :-(
Just my 2 cents on the marketplace.
My recommendation is if connecting to the iPAQ 5000 series is of utmost importance, I would replace the router with one that is more compatible.
One option though more expensive is to take a look at symbol.
available at http://www.symbol.com/products/wireless/products.html