This is a nice, simple layout! Some of my suggestions are more design-related... a few technical. And, maybe these appear this way because I'm on a Mac or some other cross-browser/cross-platform compatibility issues. But, it's good for you to know just in case!
I've attached images below to help you visualize where I'm talking about.

(main.gif is low-quality just to get it all to fit).
My stats: Firefox 2.0.0.8 on Mac OSX.
Relating to main.gif
1. On the home page. About a third down on the page, below the ad where it says, "Tagpix is a free image hosting provider." I'd bring the paragraph floating to the right to the same baseline as the first sentence on the left.
2. It may just be my computer, but I like the line-height on the paragraph in #1 (above). When there's a link, the double-underline doesn't lay on top of the sentence below. I also like the leading in the small blurbs, but the underline makes it difficult to read, I think. I'd suggest either changing the underline or making the line-height the same as the paragraph above for consistency.
3. Also, I don't know if that ad is supposed to be smack-dab right in the middle of that blurb or under the yellow box. Maybe something worth exploring.
4. Your bottom navigation links are kinda funky.

All are underlined except for "Terms & Conditions," but I can still click on it. Also, "About | Contact" share the same link for me. I don't know if this was on purpose. If so, I'd suggest getting rid of that bracket divider and just saying "About & Contact" :P
Relating to login.gif
1. Again, this may be because I'm on a mac... but it seems there needs to be more padding/margin for the login box. It kisses the content box to the left.
Relating to contact.gif
1. Same as above. Padding/Margin for contact area... and also more padding for the content box on the left. I also don't know if there was supposed to be an ad above this, but maybe adding some space between your dashed divider line at the top and the content.
Great site design and I can't wait to use it!

Hope this helps. Again, I'm on a Mac, so if this doesn't look the same on everyone else's computer, just tell me to shut up. :P