i only use the wired headset for listening to mp3s :P or watching some videos, what i do use to prevent face-input on the JAM is the brando leather case (it has a magnetic flip cover for the screen so after i dial i just close it).
for those of you thinking on getting the brando case here is a mini review.
Pros:
Nice Leather I think this is some sort of Nappa
You can sync/charge with case on
You can use headset also
Side Openning Screen Cover Flip with a place to put a spare SD or MMC card (however the 256MB + WiFi SD card from sandisk will not fit)
Thinner profile compared to the free i-mate case (note: this is without the belt clip)
Cons:
The holes could've been aligned better.
Camera hole - ok
Self-portrait mirror + speaker grill - not ok (speaker is partially covered)
Screen - not ok (a bit off)
Front buttons not ok (very off)
mic hole (bottom of ppc phone) - not ok (way off)
The latch on top actually covers the SD slot and so if you are using an SD wifi card this should be open... a big design flaw IMO. they should have gone with two thinner strips to clear this area.
I would post pics but I don't have a website to host and link them. All in all though the cons are very minor and maybe I am just very stingy in terms of cases so I am a bit harsh. I would recommend you getting the brando case for the mean time since it is definitely much better than the free one.
on a scale of 5 this case would be 3 or 3.5 max.
What I'm waiting for is a pvc skin case that covers the whole device (push thru buttons of course instead of cut-outs) with a side opening transparent screen flip. of course without the belt clip thing (i really don't like the belt clip solution-- ok maybe this could be a user option)
I've suggested this to boxwave already hehe

I'm also sure there will be aluminum cases out for this device soon. just hope they make it nicely hehehe!