Using high speed cellular service by USB cable tethering a MS WinCE based cellphone results in OK downloads but practically non existent uploads.
Filling out web based forms or sending gmail / new yahoo email may fail. Uploads fail.
The bug has NOT been fixed as of 20090923 / 184.108.40.206-43.fc11.i586. Possible workarounds:
WorkAroundA: Connect to the phone via BlueTooth instead of the USB cable. Not verified.
WorkAroundB: Use an intermediate router that can connect to the cell phone and the Fedora box. Custom made openwrt/dd-wrt or a CradlePoint router. Verified.