I use Spell Checker on my original Motorola Droid. It's a free ad supported app. It works OK (you type what you want in spell checker then paste it into an email or text or doc or whatever). Doesn't work nearly as well as the Blackberry, but definitely better than using autocomplete (especially since autocomplete does not even turn on with the slide out keyboard on the Droid).
I find the email support of Android to be very disappointing coming from the Blackberry. I had to download MailDroid so that I could save email attachments other than JPEG to my SD card. I have to type my emails in a separate app. Very disappointing. It's not a deal breaker for me yet because I have found 3rd party workarounds, but the poor email functionality is a glaring oversight in my opinion.