Hi Keith,
just thought i'd chime in.
I had a spider bite on my ankle about 6 years ago - happened in Australia. It was a little inflamed and swollen.
Being a typical male (I found the bite in the morning) I went off to work my late evening/night shift (I was a bouncer at the time)) and about half way thru my shift my entire leg was aching really bad. I managed to finish my 12 hr shift on my feet went home and slept. Got up the next day (middayish) and got ready again for work. I made it to work but went via a drugstore on the way in for some advise (they said get to a hospital) - I declined (stoopidly). About two hours into that shift i could barely stand 9my entire leg now was stiff as a board) and my groin was massively swollen. I was starting to get into some serious pain. Felt like someone was whacking my ankle every minute with a sledgehammer.
My flatmates came and pickedm e up and after alot of convincing (i hate doctors) made me go to emergency.
Long story short - they put me onto some kind of IV straight away, gave me a heap of tablets and I spent the next two weeks in bad in agony. My lymph glands in my groin and underarms and neck were the size of golf balls and there was a definate blue line that ran up my leg to my groin.
Doctors said that basically my lymph glands could no longer handle the poison and that I may have been just a few hours away from death as the poison and its effects would then travel to much more impotant organs.
Well - it took about two weeks to get over it - along with plenty of hydrogen peroxide to eat out the infection site. I lost a good deal of lfesh (pretty deep too) at the bite site.
So i got better - then about two weeks after everything had cleared up I was at work at my foot started aching - and i recogniswed the pain immediately - like a sledgehammer blow every minute or so on my foot (not the ankle this time).
I worked my shift, went home and took my boots off.
When I took my sock off I got the shock of my life. The ends of all 5 toes were green and hugely swollen. A few days later all my toenails lifted off, and with the help of a rzorblade I opened up the skin on each toe and drained what appeared at the time to be an endless supply of puss from the wounds.
Two weeks later - I was ok. My toesnails all grew back and to this day I haven't had a relapse but almost every year the bite mark will mildy flare up and get inflammed and itchy and occassionaly the skin will break but that is all it has done - thankfully.
Moral of the story - if you get bit by a spider (particularly one in Aussie) get it checked out. nasty little fookers...

Good luck.