ThinkGeek has it:

http://www.thinkgeek.com/gadgets/cellphone/e66e/#tabs

Ooh, one for the 3Gs too, and right now on sale for $30.  This is a 
flip-around keyboard, not a slider, so the hinge sticks out the side 
of the iPhone.

I found the slider case for the iPhone 4/4S on Amazon, but for like 
$60, and it's available from Chinese websites for half that.  (And 
is reported to be obviously made in China.)

I can't promise the flip-around case is made ten times better, but 
I've heard some good reports about it and only the one bad review on 
Amazon for the slider case.

Joseph - KF7QZC


On Sun, Dec 04, 2011 at 04:12:51AM -0700, Gerry Leary wrote:
>Where can you get the keyboard case for the iphone?
>----- Original Message -----
>From: "T. Joseph Carter" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Saturday, December 03, 2011 9:11 PM
>Subject: Re: OT bluetooth keyboard
>
>
>> For the most part they function pretty much the same.  For the
>> iPhone 4 and 4S, there's a clever slider keyboard case that does what
>> you'd expect.  For my iPad, I use the same kind of wireless Apple BT
>> keyboard I use on my Mac.
>>
>> Joseph - KF7QZC
>>
>>
>> On Sat, Dec 03, 2011 at 09:42:27PM -0500, Lou Kolb wrote:
>>>Sorry for the OT post but I'm looking for a bluetooth keyboard to use with
>>>our I-devices.  Does anyone know of any of these to avoid or is one about
>>>like another?  Thanks.  lou
>>>Lou kolb
>>>Voice-over Artist:
>>>Radio/TV Adds, Video narrations
>>>Messages On-hold:
>>>www.loukolb.com