Amazon USA is now selling the Google Nexus 7 tablet themselves and they can ship it direct to Singapore.
Shipping to Singapore is free for purchases above US$125. Effectively, the 16GB model is going to cost SGD $287 and the 32GB model at SGD $337. There will be no GST.
Delivery should take around 2 weeks.
If you want to buy a good tablet, the Nexus 7 is an incredible value for the money.
Here's the direct link: