As for mouser, I emailed them and asked about the UK site and USA shipping in 2013..
Thank you for your email. All goods are shipped from Texas, USA, so all the prices are excluding VAT. VAT is added at customs. If you choose UPS VAT will be paid by UPS and they will bill you together with an administration charge for doing so. If you ship with our FedEx International Priority service, goods destined for Europe are brought in through a clearing house in France - we then pay the VAT to French customs. If we have your VAT number, we claim the VAT back and your invoice is effectively zero rated for VAT. If we do not have your VAT number, then VAT is added to your Mouser Invoice.
I hope that this clarifies the situation, but if you have any further questions, please feel free to ask.
Customer Service Representative
IMO the UK site is pretty pointless, pretty much just lists prices in GBP I guess.