Big thanks to Emma for reminding me about this!
Particularly if you only worked part of a year, it's possible you may have paid too much tax while you were working. Since the tax year has ended it's now possible to get that money back from the IRD. For me, including overpayment on my student loan, this adds up to $1600!!! So I thought those that don't know about how to check if they're due a refund might appreciate some info.
These instructions are for people with straightforward income situations so it might pay to get some proper advice if your income is more complicated.
However, this is really easy - don't go paying those people you see in malls offering to do it for you for a fee!
1. You can do it all over the phone, but I find the easiest way of doing this is to
sign up for online services at the IRD website. (You need your IRD number.) Unfortunately at the moment part of the process involves sitting on the phone to the IRD to confirm your registration

but once that's done it makes your life a lot easier.
2. Once registered for online services,
login to your account. (It's case sensitive and your user ID will be in caps.)
3. Go to "Look at account information" under "View and confirm", then "INC - income tax", then "Earnings information". For the most recent tax year, click on "01 April 2008 - 31 March 2009".
4. In a separate window, open up the
Personal tax summary calculator for 2009 and click Start.
Check the second option for the first question, "I have a summary of earnings from Inland Revenue or my earnings information from the Look at account information service showing my income from these sources."
Fill in the rest of the boxes if any apply (none did to me) and make sure you select the box to say whether you have a student loan or not. Click Continue at the bottom of the page (you don't have to provide your name and personal I prefer to remain anonymous as much as possible when dealing with IRD!).
5. Flick back to your earnings information. Use the TOTAL gross income (on the far right of the page) to fill in box 11B at question 1a of the calculator. Use the TOTAL tax deductions (at the very bottom of the PAYE column - so less the ACC earners levy) to fill in box 11E at question 1a. If you have a student loan, the total value for that is also in your earnings information to plug into the box at question 6a.
Click Continue again.
6. When the results come up, at the bottom of the second block of numbers (headed 'tax calculation') there will be a line which either says "your refund" or "your tax to pay".
If you have a student loan, there will be more information saying whether you have overpaid or underpaid. (If it's an overpayment, you can choose to have that refunded or simply paid onto your loan balance.)
If the calculator came out saying you have tax to pay, and it's less than $50, don't stress, it's unlikely the IRD will do anything about it. (If there's a large discrepancy, which is unlikely, it might pay to contact the IRD about it so it doesn't come back and bite you in the bum later.)
7. If, like me, the calculator says you're due a refund, yay! Now you have to get a
personal tax summary. You might get sent one automatically (eg if you got WFF from the IRD - other criteria are on the link), but otherwise you need to
request one by filling out a form online. (They won't be sent out til later this month, but I want my money sooner rather than later so I'm doing it now!)
8. Once that comes out, you confirm the details (ph 0800 257 771 anytime between 6am and midnight - you *may* need to send them a bank deposit slip first though) and they put the money in your account! Wooo!
I should add, you can check details and request a PTS for up to 5 years ago if you haven't done this recently. If you want to do that then the earnings information is available using the online services and the calculators are all online - make sure you use the right calculator for the right year or it gives you the wrong answers.
2008 PTS calculator
2007 PTS calculator
2006 PTS calculator
2005 PTS calculator
2004 PTS calculator