Here are a few really useful site - you can arrange delivery for heavy items very cheaply compared to what you'd pay at a P/O and this will be very useful for people on here im sure!
send anything that is no bigger then 120x60x60 and weights no more then 30kgs (this company uses DHL)
www.payperdrop.eu
Again send anything that is no bigger then 120x60x60 and weights no more then 30kgs (this company uses Parcel Force)
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=360000417551
good link for sending alloy wheels
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=018
for parcels that do not fall within the above dimensions then here are a few more companies
www.chesterpost.com
www.interparcel.com
www.parcels2go.com (10% discount if you put their logo in your ebay auction)