If you haven't already visited the jobs page, then you should do so here:
http://www.coolantarctica.com/Commun...antarctica.htm
Posting in this forum that you "are available" will achieve nothing, you need to chase the jobs up yourself.
Recruitment tends to take place mainly from January to about May/June for the following season. So recruitment to go South in the summer season 2011 / 2012 will take place from Jan - June 2011.
There may be a very few jobs come up after June for the coming season (i.e. from June 2011 for 2011/2012 season), if someone previously recruited is unable to go for instance, these are by their nature rare and unpredictable as to what job/s they may be.
There are recruitment fairs, see the jobs page and also recent posts in this forum. In the USA in particular attendance at a fair increases your chances of employment greatly.
Tenacity pays off - if you don't get the first job you go for, keep trying, it shows it's more than just a whim on your part.
Here's a really useful post for US citizens from Alan Light who has wintered several times in Antarctica at McMurdo and also the South Pole station.