ESXi 3.5 does have SSH capablities but it is disabled and not supported by default. If you want to enable it, follow these steps:
- At the ESXi console press ALT-F1
- Type in "unsupported" and press Enter. You will not see the text as you type.
- You will see a Tech Support Mode warning and be prompted for the root password. Enter the root password and press enter
- Edit the inetd.conf file located at /etc/inetd.conf using VI
- Scroll down the file till you find the file that stares with #ssh, move the cursor over the # and press x
- Exit and Save by pressing ESC and typing :wq
- Type in "ps | grep inetd" and take note of the process ID
- Type in "kill -HUP <process ID from step 7>"
- You can now SSH in to the ESXi host
UPDATE: Confirmed to be working on ESXi 4.0 also