Trying to use something other than blogtitle for title in header area

Hi,
I would like to have my blog title set as one thing, having that title appear in the Title tab at the top of the page, but use a different Title for the Title that appears in the header. I have programmed in a few languages in years past, but I am not php-competent. I did dig in and tried a few things but the best I got was accidentally making the header title disappear. Luckily, I always back up before experimenting! Could you please point me to where I could insert a line or two of code to accomplish this? I don't care whether it's a hard-code hack or setting up a new variable, as long as I can accomplish this. Thank you SO much for your help. I am loving your theme, and absolutely EVERYTHING else that I want to do has been addressed in your very granular approach. Thanks again,
Bob