shifting is the best word i can come up with to describe the problem... or perhaps, able to be tilted to the left or right. at any rate, it's quick release, mounted tight on the fork but you can move it sideways, left/right, by like an 8th of an inch to the point where it rubs the brake.
is this something internal in the hub? i'm not a wrench or anything but perplexed because i don't see anything moving externally yet i am able tilt the wheel left or right. also, i assume it's not safe to ride on this wheel any longer...?
This is not necessarily a sign of imminent failure, more a matter of concern. Worst case, I believe would be some structural failure of the fork tips, so just to be sure take the wheel off and pull, push and twist and closely examine the fork ends and blades. Not likely but check. Hubs come in sealed bearing and loose/caged ball bearing varieties. Next look at the hub and check for obvious structural anomalies like cracked housing, loose spokes (it would be a lot of spokes for this to happen) etc. This is also unlikely.
Finally look at the axle/hub complex. Loose bearing hubs have a threaded hollow tube that is the actual axle and is 10x1mm threaded through which the QR slides. Check the threaded ends for looseness or side to side wobble, should be tight. If not then there are two threaded 'nuts' on each side that may just be loose. Or the bearings and races may be damaged. Some dissassembly required. See www.parktool.com and click "Repair Help" at the top right and scroll down to the stylized bike and mouse over the front hub for a pictorial essay on this. If the bearings are sealed dissassembly is more complex. One other thing that can happen in addition to bearing laxity is a broken axle. Axles are easily replaced if loose bearing threaded type, but dicey if sealed bearing type. You will have to inquire at a full service LBS depending on the hub.
thanks for the detailed advice sch... i was just messing with it downstairs and it looks like the nut on the right side, where the QR lever is was a little loose. after a little trial and error i tightened it to a point where the wheel would still spin free but the nut was tight. put it back on and there wasn't any of that shifting. yay, a relatively simple fix. the wheel/hub is a temporary replacement for an already busted wheel so i was quite angry to see this one too was broken.
the hub is loose bearing, and i've never overhauled/repacked a hub before, but was fastinated by the fact that the more you tighten the nuts on either side the more they actually press on the bearings inside. is this true? seems, well, like a less than efficient way to do things if you're always struggling to find the "sweet spot" between too loose (shifting) and too tight (bearings grind or it doesn't spin).