I had success with it most of the time, but it soft bricked my phone while I was at work. Here is what I did (when I was successful):
1. Downloaded the
Droid Fonts from here.
2. Transfer the .tff files for Droid Sans and Droid Sans Bold only to my phone.
3. Moved the .tff files to a folder I created on my internal sd card called Fonts.
4. Downloaded and installed Type Fresh from the Market.
5. Downloaded and installed AndExplorer from the Market.
6. Opened Type Fresh and replaced DroidSans.ttf and DroidSans-Bold.ttf only with the .ttf files appropriately named in my Fonts Folder.
7. In the Menu in Type Fresh, I chose Apply Fonts and when requested, I clicked Reboot.
Hopefully there is something in my procedure that you missed so you can change your fonts too.