I'm not sure whether this belongs in the Networking or Software forum, so if a mod sees this, please move it to where it's supposed to be.

Anyway, I am getting ridiculously slow transfer speeds when FTPing things to my server (running ProFTPd) and also when accessing the webserver (Apache 2) located on the same box.

I had this problem a while ago, but now, after not having used my server in a few months, it seemed to have disapred. Until not long ago, when the problem has arisen again.

The server is located on my LAN, running Slackware 10.0.

I've tried using different computers on the LAN to FTP and access the intranet, to the same result. A wired in computer (100mbs ethernet) and a wireless laptop (54mbs).

It's a great annoyance for most websites to load within a second or two (1mb ADSL) but for a page saying "Hello World" located on a computer less than a foot away from me to take 5-15 seconds.

For the first few seconds, nothing appears, and in the status bar on Firefox it says "Waiting for 192.168.1.6", then all of a sudden everything that is supposed to be there appears all at once.

Similarly with FTP'ing. (Usually use SmartFTP as my client, though have tried WS FTP, Cute FTP and numerous others, which has had no effect on the issue).

Driving me insane, any ideas?

EDIT:
Same issue when accessing the FTP / Web server from the box itself, locally. Takes just as long.

Sounds like your machine may be running low on memory. Try running

cat /proc/meminfo

and copying the result into here. If it indeed is, there's probably a process or two that's eating it all up. Run top, and type M [just a capital m] and see what the top few processes are. If you can restart or kill those services [or kill the runaway processes, if that's the case], you can probably free up some memory. Rebooting can be a last alternative.

If none of that works, reply here and I'll see what I can do.

Also run ifconfig eth0 and see if there are a lot of packetr errors reported (both on your machine and the server). You can also run a packet sniffer like Ethereal on the server and look for bad packets. It could be a number of things.

There wasn't much memory left, memory free showed about two and a half mb.

Also CPU was on 97-99% all the time, with a process called 'VI' being 95% of that. I killed that, and seems to be working fine, and most importantly, faster.

Do I need VI to be running, if I don't, how do I stop it from starting at boot?

'vi' is a text editor, so it definately should not be starting at boot. Are you sure you hadnt started it yourself? If not, it could be in a number of places:
rc.local
~/.bashrc
~/.bash_profile
~/.profile
/etc/profile
~/.xinitrc
...etc... It could be about anywhere, if that realy is the case..

I may have started it a while ago, but for text editting in the konsole I use pico. VI just shows a long list of '~'s, don't really know how to use it.

I just started VI again, and not knowing how to properly exit the program, just closed the konsole. Running top again, showed 97.6% CPU usage, with VI being the #1 offender.

Guess thats solved my little problem, just have to read up on how to use VI I Guess :P

Well, if you ever get stuck in VI again, just hit escape a few times and then type :q! [the exclamation point is part of the command]. That should quit it without saving the changes. If all else fails, killall vi.