Wikipedia is an excellent place to start your research. IF you are interested in impressing whomever is evaluating your work, tell them that there are not 4ps on Marketing, but five. The last p stands for people and it is the most important p of all; although, most professionals still forget about it. I don't know how many times I have used that same idea when doing a presentation for a client.
That's actually already covered under promotion as well if done right. Promotion is all about your target market / audience and how you're reaching them or going to reach them. You can't have a promotion section without involving people. Calling it something else in itself is just a way to make it sound "pretty" when it's being presented to clients or employers, and not an improvement over the basics at all actually. But like I said... you'll see all kinds of numbers and other "Ps" thrown in there that don't improve upon the original. 5 and 7 are the other two I've seen most often.
I suggest you look here too. This forum can give you many practical tips. Direct from webamsters involved in various aspects of marketing.
Thats really a great analysis, personally i think People is the most important P too.... cos indirectly its the very P thats our target market,, from now on i'll be using this as well in my presentations !!! Thanks!!!