I recommend trading your BTC through cryptsy in order to get the PTS. Many people complain about cryptsy but you will not find a more secure and seamless trading experience.
Setting up an account is easy and can be done in minutes. http://cryptsy.com
Once your account is established, go to your BTC and click deposit. There you will generate your deposit address. Once deposited, your funds will be available after 4 confirmations on the network.
Now head to the PTS/BTC market.
Study the orders and look at the chart. Dont be fooled by silly algorithms manipulating the market. Select an entry price you feel reflects the true market price. (If you are after very large quantities, your entry to market would differ. There are strategies to move large volume without causing wide price fluctuations.)
Once you have your PTS, withdraw to your local wallet. Make sure your security is top notch, that the wallet is encrypted and you have safe backups of the private keys.
As you embark on this journey it may be wise to consider Angelshares for your portfolio. I strongly suggest reading thoroughly through the procedure.
Hope this helps with the PTS