Heya, welcome and congrats!
I too have a Galaxy Tab and have just started to mess around with it. Quite a sweet device, though a tad on the heavy side. Still, excellent performance IMO so far.
For reading ebooks on Tab, I strongly suggest the fantastic
fbreader application. Free! It is incredibly fast to load up and is far superior to the ebook reader that came pre-installed on my Tab [no idea what the program name is though...possibly aldiko?]
cheers and enjoy
-les