Frustration mounts in everyone looking for answers on adding memory to WP7 phones, specifically the Samsung Focus. AT&T and several other outlets such as BestBuy sell the SanDisk Mobile 16GB microSDHC card. This one Works: You must follow AT&T/Samsung’s instructions to the letter. These cards are not used as removable/swappable memory but are the same as adding more RAM to your computer. The Focus must be in factory default mode so either insert the memory at the very beginning or reset the device. Follow the instructions. A couple or three caveats; ensure that you have inserted the microSDHC completely into the provided slot, release the power button promptly at the appropriate time in the instructions (if you hold it too long you will go into download mode which is designed for updates and you may need to remove the battery to reset, and follow the instructions. Just like RAM in your computer, your total memory will show up in Settings - About and the total will show as the total amount less system resource use. So the 8GB built in + 16GB card will not = 24GB but around 22 - 22.5GB. Did I say that this card works? Yes it does.
It makes surfing the web and reading texts much easier in bright sunlight. The brilliant display allows you to quickly access the information most important to you with Live Tiles on your start screen.