you should look into Android and bluetooth HID support. A lot of bluetooth keyboards require you to use HID bluetooth profile (which is actually a pretty standard thing) but Android doesnt natively support it.
It looks like theres a way to manually get HID bluetooth keyboards to work by typing in some command switches and maybe writing a script to semi-automate it. Or there is a for-pay program y ou can download but reviews seem to suggest it may not be reliable and might be buggy.
So in short, if the keyboard uses HID bluetooth (like my stowaway/igo bluetooth keyboard) it wont work out of the box with our phones. It'll see and try to pair, but thats the end of it.
Quite sad really, as my 5 year old Dell Axim winmo phone could do it, and so does the iphone/ipad/ipod as of a few updates back...