Used to have windows 98.  In the bog standard paint program, I could make a colour transparent, to enable it to be used on a website (make a transparent backgroud for logos etc).

With windows XP, that I have now, I can't see how to do this with the version of paint with it.  I don't have coral draw or anything like that on my machine now.

Any tips as to if I can do it with paint (being blind ), or any free software floating around??

Is this what you mean...

The Help system for Paint says...

To specify opaque or transparent drawing

To draw an opaque image, on the Image menu, click Draw Opaque and make sure a check mark appears next to it.
Selecting Opaque specifies that the existing picture will be covered by the white background of a selected area in Paint.

For example, in the image at the left, notice that the small dotted box includes a white background around the green box. Also notice that the white background covers the larger image behind it.
To draw a transparent image, on the Image menu, click Draw Opaque and make sure the check mark does not appear next to it.
Turning off Opaque specifies that the underlying pictures will be visible through the background of a selected area in Paint.

For example, in the image at the left, notice that the small dotted box is clear and the green box displays inside it. Also notice that the content of the image behind it is visible right up to the green box.