See your name up at the top right under the GardenStew banner....hold your mouse over your name and a list of options will show up. Click on Conversations....that's what PMs are called now.
Alternatively you can click on the Inbox link in the main menu, or just hover over it to see a list of recent Conversations To send a Conversation to an individual member click on their member name anywhere on the forums and the click the 'Start a Conversation' link in the box that pops up.