I got this in my inbox this morning and i thought i might post a link to it here.
It is a pdf called Tax-smart investing - What share investors need to know and it is published by the ATO. It provides some very general and basic information in terms of tax implications of share purchases and sales and will assist in keeping the ATO from taking you to the cleaners.
I realise it is very basic but for those that are knew or just give the accountant a shoe box full of receipts at tax time you may get something out of it.
Please remember this is general advice and you should do you own research for your own circumstances prior to making any investment decisions