Do I need a ttl to usb converter or can I connect the vcc, gnd, tx and rx pins of the mini such as this one
http://www.ebay.co.uk/itm/261523991240?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
to the UNO pins vcc, gnd digital 0 and digital 1 after removing the atmeg chip and just program as if it was the chip on the board?
Yes.
Or leave the chip in place, and connect the Uno Reset to Gnd.
You will need to press Reset on the Promini when you see
"compiled xxx bytes of 32xxx bytes" in the IDE.
If you select File:Preferences and turn on Verbose outputs, it can be easier to find the right time to press it.
matelot:
Do I need a ttl to usb converter or can I connect the vcc, gnd, tx and rx pins of the mini such as this onehttp://www.ebay.co.uk/itm/261523991240?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
to the UNO pins vcc, gnd digital 0 and digital 1 after removing the atmeg chip and just program as if it was the chip on the board?
Also wire a reset to reset connection as that should allow the IDE auto-reset to function when you proceed to upload, otherwise you will have to master the 'well timed manual reset switch' dance.
Use the1.5.6 r2 version of the IDE software. The method Iike to use is as follows:
Hook it to the USB to seriial thing.
Fire up the 1.5.6-r2 version of the softareware.
Have fun coding.
You miss the reset, don't you? I have that setup but with a Diecimila instead of a UNO board.
I am wiring it similar to the ng picture at the bottom of this guide
but to a UNO.
this includes the reset.
I think the mini already has a sketch of the blink program in it because the led on the board and one I have added to pin 13 are flashing about twice a second.
If I try to load anything in to it such as the blink program with the delays set to 5000 I get
avrdude: atk500_getsync(): not in sync: resp=0x00
in orange in the bottom box of the arduino sketch building program.
Even if I alter tools/board to 'arduino pro or pro mini ' and alter tools/processor to 'atmega 328(5v,16 MHz)'
the rx led on the UNO flashes a few times when the loader starts loading but the flashing lights on the mini continue to flash.
Pressing the reset on the UNO does nothing unlike the comment in the above link says it does on the NG.
Is there something else I need to do?
I have discovered how to do it.
use the drawing at the bottom of this page
mine is an UNO not an NG but wire it the same.
The UNO has a rst next to the 3.3v socket but it works with the reset on the mini set to either pin 1 or the reset socket of the UNO.
go to tools/board on the loader and tick arduino pro or pro mini.
go to tools/processor and check 'atmega328 (5v 16MHz') is checked.
Make sure you have good connections to all the five holes of the mini (I used a bread board and soldered the supplied strips to just the required holes as I intend using the boards without the rows of pins). I think I might have been getting the error message seen before due to bad connections.
The boards I bought already had a programme in them flashing at 1/2 second intervals which showed on the onboard led and pin 13 when I touched it with an LED.
I am using 1.5.4 version of the software.
Just for clarity ......it is rx on the UNO to rx on the mini and tx on the UNO to tx on the mini.
Thanks to all who gave me a sensible reply.
Good Work! 
Karma for you!!!
Can you please change the subject of the first post to "SOLVED...", to every one that have the same question find the answer easily?