EDIT: DiskAid is far far easier. Ignore the rest of this tutorial.
Disclaimer: Technically you're not SSHing... You're just making a USB connection that accomplishes the same thing.
So anyhow, I had a need for this setup due to a really complicated WiFi situation that made SSHing a huge ordeal... So here we go!
1. Download and install:
MacFuse
Disk for iPhone
Then restart your computer.
2. Plug in your iPhone.
3. Open Disk for iPhone. Media will show up on your desktop.
4. Click on the Disk for iPhone icon in the status bar and select root.
(Yeah, I know, pic taken from their site because I'm too lazy to go make screenshots and this is pretty dead simple)
5. Root will show up. Now the slightly tricky bit is that Aliases within the root directory do NOT work. So, go to the following: private/var/stash. Or, with root mounted, open Finder, click Go on the status bar and select Go to Folder and copy and paste "/Volumes/Root/private/var/stash."
The stash folder is where you'll find Applications and Themes, among other things. While there are other things you can do with SSH those two are by far the biggest ones.
And there you go, that's all there is to it. Quick protip so you don't have to bother with folders though: If you make an alias to the stash folder and put it on your Mac somewhere, all you have to do is connect the iPhone, start Disk for iPhone, select root, and double click on the alias to get where you need to go.
Disclaimer: Technically you're not SSHing... You're just making a USB connection that accomplishes the same thing.
So anyhow, I had a need for this setup due to a really complicated WiFi situation that made SSHing a huge ordeal... So here we go!
1. Download and install:
MacFuse
Disk for iPhone
Then restart your computer.
2. Plug in your iPhone.
3. Open Disk for iPhone. Media will show up on your desktop.
4. Click on the Disk for iPhone icon in the status bar and select root.

(Yeah, I know, pic taken from their site because I'm too lazy to go make screenshots and this is pretty dead simple)
5. Root will show up. Now the slightly tricky bit is that Aliases within the root directory do NOT work. So, go to the following: private/var/stash. Or, with root mounted, open Finder, click Go on the status bar and select Go to Folder and copy and paste "/Volumes/Root/private/var/stash."
The stash folder is where you'll find Applications and Themes, among other things. While there are other things you can do with SSH those two are by far the biggest ones.
And there you go, that's all there is to it. Quick protip so you don't have to bother with folders though: If you make an alias to the stash folder and put it on your Mac somewhere, all you have to do is connect the iPhone, start Disk for iPhone, select root, and double click on the alias to get where you need to go.