I will try and keep this post updated for the instruments that I use.
S&P USD 50 is the Standard and Poor 500 Equity Index at 50USD per point. Which means you make or lose 50USD for each point the index moves.
FTSE 100 £2 is the Top 100 UK Companies listed on the London Stock Exchange. Which means you make or lose GBP 2 for each point the index moves.
FTSE 100 Put 3550 May 2009 is an Put option giving the buyer the right to sell the FTSE 100 on May at 3550. The level of the sale could be variable for example 3600 / 3700 - there are a range of options available at those values.