Custom field (date) > but if past this date to display additional text!

Hi all.

I have a question regarding custom fields.

I have been using them for a while now, and they are serving well.

I currently have a category which has posts which each include an ‘expiry date’ which I enter using a custom field when writing the post!

All works great, and this shows up OK in my template!

But what I would like to do is for additional text to show up if this date has passed.

So if the date entered has expired, then the post will show ‘Expired’ somewhere in the template, or possibly an image.!

Any ideas how this can be achieved?

Many thanks!