What's a good iPhone app that will let me view files on my network?

I'm looking for an app which provides functionality similar to Apple Finder's "SHARED" feature, or Microsoft Windows Explorer's Network Neighborhood. Basically, I should be able to use my iPhone to access shared files on computers that are on my same network. Any suggestions?

Specifications:

1. Doesn't require software to be downloaded/running on any of your machines. The only piece of software the solution requires is the iPhone App.
2. You should only be able to access files that are shared on the network.
3. You should be able to access files on network drives that aren't connected to computers (e.g. NAS).
4. Doesn't require jailbreaking the phone.

Examples of things I'm not looking for:

• A screen sharing solution (e.g. remote desktop, logmein, etc.), this violates #1 and #2 above.
• Far Finder: violates #1 and #2, possibly #3 as well.

I think NetPortal by Stratospherix may do what you want. I use their FileBrowser for iPad, but I haven’t tried NetPortal, which is their iPhone version. They also have a free NetPortalLite version.

(Sorry, I don’t have the rep to include more than one hyperlink.)

You are going to need an AFP or SMB client then - thats what the machines themselves are doing. I don't think there are any AFP or SMB clients in the app store - therefore you may have to jailbreak your phone to use one - and after a few searches, still don't know if there are any available (I do however find a lot of options for mounting your iPhone on your Mac).