Yeah, I think so too.  When I tried to run

```
./spark-ec2 -i ~/.ssh/berkeley-laptop.pem -k berkeley-laptop -s 10 -t m1.large --spot-price 0.25 --region us-west-1 launch test_cluster
```

I received the error

```
Setting up security groups...
Searching for existing cluster test_cluster...
Launching instances...
ERROR:boto:400 Bad Request
ERROR:boto:<?xml version="1.0" encoding="UTF-8"?>
<Response><Errors><Error><Code>InvalidAMIID.Malformed</Code><Message>Invalid id: "latest" (expecting "ami-...")</Message></Error></Errors><RequestID>6c4888ae-e4b6-4539-b0be-047268fbcdd5</RequestID></Response>
Could not find AMI latest
```