Essential spelling for writers
The wonderful site askoxford.com is a treasure chest of information on the differences in spelling and meaning between nations.
An example below:
American Spelling
The main differences between American and British English spellings are given below:
* British English words that end in -re (e.g. centre, fibre, theatre) often end in -er in American English (center, fiber, theater).
* British English words that end in -our (e.g. colour, humour) usually end with -or in American English (color, humor).
* Verbs in British English that can be spelled with either -ize or -ise at the end (e.g. recognize/recognise) are always spelled with -ize in American English.
* Verbs in British English that end in -yse (e.g. analyse) are always spelled -yze in American English (analyze).
* In British spelling, verbs ending in a vowel plus l double the l when adding endings that begin with a vowel (e.g. travel, travelled, traveller). In American English the l is not doubled (travel, traveled, traveler).
* British English words that are spelled with the double vowels ae or oe (e.g. archaeology, manoeuvre) are just spelled with an e in American English (archeology, maneuver).
* Some nouns that end with -ence in British English (e.g. licence, defence) are spelled -ense in American English (license, defense).
* Some nouns that end with -ogue in British English (e.g. dialogue) end with -og in American English (dialog).
Commonly confused words
American / British
Jumper / Pinafore Dress
Sweater / Jumper
Rubber / Condom
Eraser / Rubber
Pants / Trousers
Panties / Pants
Chips / Crisps
French Fries / Chips
Different words for the same thing
American / British
Cart / Trolley
Diaper / Nappy
Eggplant / Aubergine
Fall / Autumn
Line / Queue
Scallion / Spring onion
Snow peas / Mange tout
Trunk / Boot
Vacation / Holiday
Zucchini / Courgette
