Oracle Fusion Middleware 11G Release 1 was officially launched by Oracle on the 1st July 2009; included in this release are the 11G version of WebLogic, SOA Suite, WebCenter and Identity Management. You can download all of the required components from http://www.oracle.com/technology/software/products/middleware/index.html.
Installing the Oracle SOA Suite is pretty straight forward; however the one gotcha is the install of JDeveloper 11G does NOT install the SOA Design Time. This is not really an issue as JDeveloper automatically checks for updates (including the SOA Design Time) and will prompt you to download and install them (alternatively select Help->Check for Updates).
However the SOA Design Time is 200+ MB in size. So not a trivial download, particularly if you are installing JDeveloper in multiple environments. Ideally it would be nice to be able to download a local copy of the SOA Design time extension which can then be installed in each environment that is required. Well fortunately you can do this by going to the Oracle JDeveloper product updated center shown below. From here click on the download link for the SOA Oracle Composite Editor (circled below).
To install the design time, within JDeveloper select Help->Check for Updates. Click Next and Select Install from Local File and browse to where you saved soa-jdev-extension.zip. Click Open, click Next and then Finish. JDeveloper will then install the extension; finally restart JDeveloper when prompted.