lol i had to learn that lesson with a waste of 25 bucks lol, but its ok, lucky i have a mp3 player capable with a 2gb micro sd lol.
I had the same problem using Generic Transcend Micro SD. My cell phone dealer sold me a Sandisk SDSDQ2048A10M 2GB Stick and it works like a charm.
we use microsd cards in one of our olympus digital cameras as well as one of our phones here, the motorola krazr. they are sooo small and delicate looking. it sure makes my regular sd card in my treo look huge. i think its good they are making flash memory chips smaller. it saves space on the devices we carry around and microsd cards can use an optional sd card converter so it can be used on existing gadgets. when the prices come crashing down, it will be win-win for new and old devices.
OCZ SD Hi-Speed 4GB for Vista Readyboost here! You should also look into the transfer rate before buying, if you are gonna use one to transfer huge files.
It's not even just cellphones... whenever you use any external memory, there's a (very, very) small chance the device might not be compatible with either the brand or the size of the card. And some older devices, even those that are only a couple of years old, may not work with high speed memory.