Overclocking is safe if done correctly. However, the proper way to overclock a CPU is to change the multiplier and Vcore in the BIOS rather than using additional software. But AMD Overdrive should be fine. Just manually change the voltages. Don't use the auto voltage feature. It will always use more than necessary.
Obligatory statements:
1. Never overclock with a stock cooler
2. Make sure to read an Overclocking Guide
3. Monitor Temps
4. Every CPU is different. Your results may not align with others.