To download the latest PowerShell Open Source just go to the link below:
https://github.com/PowerShell/PowerShell
Just remember to remove the previous version, and any existing folders as this will be resolved later.
To download the latest SQL Server vNext just check the following Microsoft blog post as the new CTP 1.1 includes version both Windows and Linux:
SQL Server next version Community Technology Preview 1.1 now available
Max has additional links and resources in that post as well.