Check out these how-to videos by Luke Healey on loading 120 film onto reels for at-home DIY film processing.
 
Loading metal reels:

 
Loading Paterson plastic reels:

See what happens when alspix—the man who brought us the now-legendary matchbox pinhole camera—processes film in year-old, over-used C-41 colour negative chemistry from a DIY kit. The results are surprising!
Read about it at Alspix Stuff.
He used this Nova C-41 kit, which is available in the UK. For those in the US, check out the [...]

Check out Eben Ostby’s plans for a 4×5 large format sheet film developing tube. View a larger, more legible version of the plans and construction notes on the photo’s page on Flickr.

It turns out that when I reviewed the HP Combi-Plan T 4×5 daylight sheet film developing tank and called it a "dodgy, leaky piece of shit", I may have vastly under-stated my case.

I just wrote a review of the HP Combi-Plan T 4×5 daylight film developing tank that explains why I think it’s a steaming pile of crap for daylight processing.
Read the review