Interoperability of Bitcoin clients Is it possible to operate on the same wallet from multiple devices? If I run, for example Android on a device, and Windows/Linux on another, how do I share the same private key(s) of my wallet between these device so I can send money from any of them?

Are the wallet files someway interoperable between clients? Is there a dedicated import/export tool?

I'm mainly interested in this client
You can use online wallet, like StrongCoin, then it doesn't matter where you access it from.
You need to use an Android client that allows for private key import/export. I'm not sure which Android client does this, but for Windows/Linux you either can look for some tools for altering the wallet.dat for the standard Client, or use an alternative client with import functionality (as far as I remember, MultiBit can do that, but I'm not 100% sure).