weight in kilograms and shipping method

can some one please help me please i wana change my zencart website weight in kilograms now its in lbs please .and i wana help in how can postage method calculate atoumatic in my website example when some one buy 4kg or 6kg weight things to my website and its postage is equal to according to uk standard parcel rate 4kg is £7.06 or 6kg is £9.58 then its will charge them £7.06+product or £9.58+product.

i don't know how can i create this even i read zencart threads but still can't know what can i do so please help me in this matter plese.
i want to make my postage method like this chart because i just sell my products in UK not in other countries so please help me .Thanks

Maximum weight Price
2kg £4.41
4kg £7.06
6kg £9.58
8kg £11.74

You could try searching the forum.

For instance: http://www.zen-cart.com/forum/showthread.php?t=35390

Also, if you are in the UK I can recommend the Big Royal Mail mod.

But searching the forum will turn up all the info you need for this.