initial amount of cDNA - (May/06/2007 )

Hi all,
I'm new in Real time world and doing gene expression study, these are my assay;
I did RNA extraction with Trizol, use nanodrop to quantify RNA concentration and make cDNA with superscript kit (maximum 5ug/reactions in total 10ul, so I can put 8ul of RNA in reaction to get as much as cDNA) thus the amount of cDNA will vary depend on the initial RNA. I assume that I got 80-90% of cDNA from total RNA. In real time PCR plate, I made standard curve run along with tripicate cases and control samples. My questions are ...
1. I must run serial dilutions on every plate? can I use the standard curve from other plate?
2. How much cDNA of cases and control samples to put in reactions? Do I need to equallize the concentration of all cDNA samples before put in real time reaction?
3. How many house keeping genes to normalize 3 target genes? Can I use only one for those three genes? and can I use nuclear house keeping gene for mitochondrial target gene?
4. How many fold changes are significant?

any other recomend welcome
Thanks

you must run serial dilutions on every plates.

we use 1 ug RNA to convert in cDNA. in reverse transcription reaction the reaction volume is 20 ul and i take 1-2 ul of sample from the pcr reaction tube and use it for real time pcr.

i cannot understand what do u mean by normalize 3 target genes but i use 2 housekeeping genes each time for many target genes

Many thanks for your answer
I did what you said, just feel that it's waste time and reagent and just got the same efficiency