Hi, If you have a gas dryer.
The most common problem with a gas and no heat is the ignitor going bad...

Here is a tip that I wrote about that problem...

Gas Dryer not Working Gas Dryer Not Heating
http://www.fixya.com/support/r4398592-gas_dryer_not_working_gas_dryer_not

If your dryer is electric..
There could be a number of different problems...
Check out this tip that I wrote about this problem...

Electric Dryer won t Heat
http://www.fixya.com/support/r3866345-dryer_troubleshooting_electric_dryer_won

heatman101