Ooh, lucky you! You need to get salt and sulphate free shampoo or it washes out much quicker than the 3 months. The stuff the salon sells is pretty dear but you can get it on ebay for less - just search for brazilian blowdry shampoo. I'm keeping my eye open for another one coming up - I miss my smooth shiny hair :)
Oh - one last thing. When you book it, make sure you don't have any plans for the next few days. You can't wash it for 4 days and you have to keep it down and straight, so no clips, bands or scrunchies. By day 3 it gets a bit yucky ;)
That page doesn't come up Euphemia, but I presume it's about the formaldehyde content. The stuff used in the US does have a highish content, but the stuff licensed for the UK doesn't. I read a lot of scare stories before I got mine, but they were all US cases and the product is different.