I recently purchased a Netgear ME102; a low-cost 802.11b wireless access point. My primary wireless device is an Acer C102 Tablet PC which has in-built wi-fi support using the Orinoco chipset.
In unsecured mode, the Acer and the ME102 behave nicely, but as soon as WEP is enabled they stop talking completely. Oddly, there are no errors; the signal strength shows as full... but access is completely dead. After a lot of experimentation with 40-bit keys, 128-bit keys, varied security settings, I stumbled across the solution.