I haven't seen this problem, but I never looked at my storage space to see how much I had left. My phone did throw up the flag that it was running short of storage space, probably because I have every app and their mother downloaded to my phone for testing
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Remember that this is kinda like the Beta of the G1, I've seen people asking the same question related to storage, so they'll probably alter the source to make all apps to store on the memory card and leave the 256 megs of internal memory to browser cache.
It's comin' out of the pipe, hang in there.