I bought 2 of em... hate buying singles. I got em for ~$35 for the pair from toysdownunder.com - but their prices seem to have gone up. Maybe I got em on sale by chance. Not sure actually.
Hooking up the SpeakJet by itself is easy - you need almost no external components for a basic setup. The majority of what you see is a simple low-pass filter feeding into the amp circuit which pretty much came straight from the LM386 datasheet. If you're using an external amp or powered speakers you could just go with a line-level output and forgo the LM386 amp setup. Pin 18 on the SpeakJet is output to the low-pass filter. Pin 10 is input and that's wired through a resistor into the header which goes to the Arduino pin (which is setup with the SoftwareSerial lib). The 3 other pins going to the 4-way header are for the SpeakJet status indicators (Ready, Speaking, Buffer half-full). The rest of the connections are used for setting up certain modes that I didn't care about.
The SpeakJet can be setup to respond to 16 specific events and play canned responses (you can flash the EEPROM yourself with custom messages via the serial connection). That's what most of the pins on the far side are for, except for a single ground connection
There's all this other stuff it can do with regard to RC servo's etc, but I kinda skimmed that section 'cause it ain't relevant for the moment.
Cheers,