I noticed that I had Google Books and Google Shopper in my Android Market account as “installed” however I guess that was from when I was running Froyo with my UK SIM card, as it won’t let me re-install it on Gingerbread with my French SIM.
So I stuck my UK SIM in and lo, I saw Shopper listed in Market on the phone! So I installed it and it works fine. My UK SIM also seemed to enable “SIM Toolkit” which apparently adds some localised functionality (maybe 3G stuff too?) as it didn’t work with the French SIM back in it and it was gone upon reboot – well actually I installed CM7 N84 and wiped data, so no wonder it went!
I thought that swapping SIM’s all the time is going to be a hassle just to install/update apps between countries, so I downloaded MarketEnabler which temporarily switches your gsm.sim.operator.numeric property to whatever you want. It comes with a list of pre-defined carriers such as T-Mobile USA and Orange UK. I installed Books using it, and it works fine too.
Don’t forget that to use Google Voice you just have to set your GMail language to English-US as described here, apparently if you have a USA GMail account (with billing address) you can even make/receive free calls outside the USA…..