Overclocking / temp Monitor

I have a ASrock 775i65G with an Intel Pentium D 915+.

I am looking to overclock this if it is possible, and wanted to know of the best way of doing this and what software should be used, whilst doing this i want to keep an eye on the temp of the processor as I have heard they are hot beasts, what will monitor the heat best for me.

any webbys people can direct me to would be great as well.

Many thanks in advance

Nick