I know nothing about Macs - I work with Windows based machines all day.

A guy at work has a Mac Book with 160Gb hard drive which is almost full so he has asked for my help fitting a new bigger one.

I've had a look at his existing hard drive and it is a sata one so it should be a case of getting a 500Gb sata hard drive popping it in an enclosure then getting his existing hard drive to "clone" over to this new one. When finished remove the old hard drive and fit the new one.

I assume this plan will work but what software to use to clone a Mac hard drive?

Any suggestions?

Hardware wise, you're spot on.
I'm pretty sure you can do cloning, however I've never done it.

If no one gets back here in time, I'd get him to grab an external disk, create a full system Time Machine backup, then installed the new drive, install the Os again and restore from the Time Machine backup (can do this during installation IIRC).

It takes longer, but could be a work around if no one else comes back

I'd also suggest poking Saspro or Caz

Two options SuperDuper! or Carbon Copy Cloner both will do clones. I have used SuperDuper! when the source drive was not 100% and it allowed me to clone a working drive perfect for an upgrade. Both are cheap.

I cloned the drive to an external drive rebooted to the external clone, then reformatted the internal drive and cloned back. All remarkably simple. Replacing an internal drive as an alternative to the reformat might work just as well. You can then still reboot using the external drive and use it to format the new internal drive prior to cloning back onto the new internal.

Carbon copy clover is basically free. It's donationware and does a good job of cloning.

+1 for Carbon Copy Cloner...
http://www.bombich.com

No obligation to donate, except for that warm feeling - personally I've used it a lot so I've donated, but it works fine without having to part with any cash.
Will take a few hours to clone, before setting it running check the following on the Mac...

1. It's plugged into a power source, obviously - otherwise it's shut down when the battery runs out!
2. Check Energy Saver options are set so it doesn't automatically go to sleep
System Preferences > Energy Saver
(you can set the display to sleep if you like, just pull the other slider to "Never" and un-tick "Put the hard disk(s) to sleep when possible" check box)

Once completed, swap drives, put the old one into the enclosure and connect - then restart with the "Alt" key held down, where you can select the external drive (the old one) to boot from. Launch Disk Utility, select the new drive and format it by going to the "Partition" tab - select the Options button and select the "GUID Partition Scheme" option. OK that, then select "One Partition" in the drop down menu, making sure it's set to "Mac OS Extended (Journalled)" - click Apply and it'll erase and re-partition the drive for Intel Macs to boot from.

Then, once you've erased the new drive (the internal one), run Carbon Copy Cloner again from the external drive - clone the external across to the internal one and once finished go to System Preference > Startup Disk and make the internal one the default boot drive. Restart, and all should be back to normal - except you'll have more free space on the drive.

Certain software might detect a change of hardware configuration - for example, QuarkXpress does - in which case you may need to re-activate it. Most software will run just as before though.

EDIT: I've done it the other way round than you originally said, but it'll work that way too (i.e. clone first to new drive in enclosure, then swap drives over) - just remember to erase the new drive first using Disk Utility and to use the "GUID Partition Scheme" option - otherwise Intel Macs like the Macbook might not be able to boot from it.

Thanks for all your advice and help.

Looks like Carbon Copy Cloner is the way to go

His new hard drive should be with me at work on Wednesday - he also decided to get me to change the ram from 2 x 1Gb to 2x 2Gb but that looks very straightforward.

Will let you know outcome!

The alternative route (slightly longer, but to be honest, the one I'd recommend) is to pull the old HD, stick in the new one.
Put old HD in an external case.
Install fresh OS on new HD.
Use the migration assistant (you may need to leave it for a few hours) to pull over the apps/docs/settings.
Very little will have changed, but again, some software may need reactivating.

Thinking about it, your original route would probably be the fastest, and maybe easiest...

1. Put new drive in external enclosure.

2. Reformat new drive using Disk Utility - Partition tab, click options, use GUID Partition Scheme, Click OK, then use Mac OS Extended (Journalled) format on the 1 partition.

3. Use Carbon Copy Cloner to clone existing drive across to external.
4. Shut down and swap drives.
5. Restart with Alt key held and select new internal drive to boot from.

Let us know if you have any issues, but it should be very straightforward.

Well we're on our way!

Put new hard drive into enclosure and got it formatted as Steve74 suggested.

Downloaded carbon Copy Cloner and now got it running - looks like it will take about 3hrs so will have another look just before 10pm to see how its doing.

Well just finished.

Machine now has new drive in place with 360Gb free and appears to be fine

Many thanks for all the help & suggestions guys - much appreciated.

Not quite so afraid of working with Macs now