Less than a day after being officially announced last night in London at Samsung’s Unpacked 2012 event, the Galaxy S3 is already available for pre-order in the UK on major carriers, where it is expected to hit the market on May 30. O2, Vodafone, T-Mobile, Orange, and Three will offer the Galaxy S3 on contract when it comes out.

Those looking to pre-order an unlocked, contract-free Galaxy S3 can get one at £499.99 (about €615, or $808) from Carphone Warehouse, who will also be giving away free accessories like a 32GB SanDisk MicroSDHC card, ZAG InvisibleSHIELD screen protector, and an in-car charger. Clove have listed a £549.99 price for the unlocked, sim-free S3, while Unlocked-mobiles.com lists it for £549.98. Carphone Warehouse and Phones4U will also be offering the S3 for free on plans starting at £36 per month.

The specs of the Galaxy S3 include a quad-core 1.4 GHz Exynos 4212 Quad processor with Mali-400MP GPU, 1 GB of RAM, 16/32/64 GB of internal memory with micro SD support, a 4.8 inch HD Super AMOLED screen, an 8 megapixel camera with 1080p video recording + a 1.9 megapixel front facing camera, a 2100 mAh battery, and Android 4.0 Ice Cream Sandwich with Samsung’s TouchWiz UI laid on top.

All of these prices are for the 16 GB version of the phone, and if history is any guide, the 32/64 GB versions will be priced quite a bit higher. Are you pre-ordering one today or will you be waiting  for some hands-on reviews of the phone before placing an order? Let us know in the comments.