hey guys i have dell inspiron 9100 with p4 2.8 ghz proc. , a ati  mobility radeon 9800 video card . i was wondering it s possible to overclock my computer   mainly my processor . ( i already have overclocking tools for my video card.)

Go into bios and see what overclocking options you have. Since it's a Dell, don't expect much.

Yeah since it's a Dell, unless they've changed how they do their BIOS lately, about 99% of the BIOS options will be locked.
 
I wanted to do the same thing on my old XPS 600, i was annoyed to say the least.

Well i found some overclock tools to help my overclock it. but im not sure on this perticular computer how much i can overclock it safely without overheating it . Any one know a good range to try to keep my temp. at? and  Maybe a setup they use . im using cpufsb  and the highest ive gotten it with hesiatation is overclocked to 3.2 ghz at :  1:68c and hdo temp at : 41c.  Any one know how much overclock  or temp would be to high for this setup?

Cpu core temps should be under 65C to consider it safe. And that's 100% load temps using Prime95 small FFTs test.