What is the safest way to perform backups of my partitions? The partitions on my phone are visible on /dev/mts/mtsX, and I'd like to copy the contents of those files onto my sd card for safe keeping. Is it safe to just say: 

cat /dev/mtd/mtd0 &gt; /sdcard/mtd0


Because I'm not so sure if it's safe to use cat on binary files. Maybe there is a port of dd?
cat is a very bad idea here. If you really want to make a backup on partition level, rather take a look at dd. What you probably want to do is something like

dd if=/dev/mtd/mtd0 of=/sdcard/mtd0.image


For more details, you might want to consult the dd Man Page. Remark: I'm not sure whether the dd shipped with Android supports the full list of options, so you might have to try out.