There are two ways to get Windows 10 Technical Preview Build 10049.
Those who are playing with Windows 10 Technical Preview Build 10041:
Via Windows Update
In the Start Search space type in windows update
Now click check for updates. If you don’t find fbl_impressive 10049 as update then click Advanced option and check the drop down menu under Choose how preview builds are installed. If there is Slow then just switch over to Fast.
Microsoft will publish ISO for this preview later when they push it out to the Slow ring. So those who like to go for a Clean installation have to wait till it is available for Slow ring.