My first Jolicloud Tip: if you want to try Jolicloud alpha release get a decent USB key.
Jolicloud, the EasySimple netbook OS, is available by download. That means that when you receive your invitation code, you will receive an email with a link. Follow the link and start the download.
All the Jolicloud installation package weights, at the moment, just 660 mega so you will be fine with a 1 Giga USB key.
But as @jolisupport (the Twitter support of Jolicloud) has just written : "Take a good quality keys for 90% of install issues were due to a usb key with defect ! forget promo usb keys and get a real one !"
So, get a decent USB key and do not go for a cheap or a promo key !