Can the blk0001.dat and blk0002.dat files be deleted? I have a Bitcoin installation on an SD card, and the blockchain files (blk0001.dat specifically) take up nearly 4 GB of disk space.

Can the blk0001.dat and blk0002.dat files be safely deleted to free up space on my SD card? Will the blockchain just be downloaded again next time I run my bitcoin client?
You can delete them just fine, as long as you delete blkindex.dat too. They will be downloaded and processed again. This will take a while, these days, though.