The site should be running a little bit quicker now, although the speed difference is probably unnoticable. I have finally got around to caching some of the common data, so that the pages don't have to hit the database as frequently. There were a few pages that were hitting the database over 10 times, and these have been cut down to 1 or 2 times now. There is still a little bit more work to do on this but it is 95% done.
On a seperate note, I have decided to store all times as UTC time (or GMT time) in the database and retrieve them as they are. Previously, the time was stored as the server time, which was 4 hours different to GMT. However, this caused many problems with archiving the blog posts by month, and with the issue of daylight savings time. All times displayed on the site should now be in UTC time, and any bits of text like 'Posted 2 hours ago' are based on UTC time.