Don't worry, it is not as bad as it seems. It doesn't effect your design in anyway and takes up only a little bit of space.

Below I included the source for putting the 'Geocities' Logo and Link on your page. Just decide where you would like the link to appear and then type in the source.

Many of the pages you see in the Neighborhoods of Geocities display this particular image.
You do not need to copy this image to your own directory. It is already linked from the Geocities image files.

THE SOURCE:

Use the following code:

This page hosted by <a href="/"><img src="/pictures/gc_icon.gif" border="0" alt="Geocities"></a> Get your own <a href="/">Free Home page</a>

WILL LOOK LIKE:

This page is hosted by Get your own Free Home page

Don't like it there?, why not CENTER IT:

Use the following code:

<center>This page is hosted by<a href="/"><img src="/pictures/gc_icon.gif" border="0" alt="Geocities"></a> Get your own <a href="/">free Home page</a></center>

WILL LOOK LIKE:

This page is hosted by Get your own Free Homepage

DIFFERENT ICON:

Use the following code:

<center><a href="/"><img src="/pictures/bhi_ball.gif" width="18" height="18" alt="GeoCities HomePage" border=0></a> Get your own <a href="/">Free Home Page</a></center>

WILL LOOK LIKE:

Get your own Free Home Page

There are many ways you can link back to Geocities so I guess it comes down to your preference.
As long as there is an accessible link back to www.oocities.org, I don't think they mind how you display it.

FRAMES

If you decide to have a 'Frames' version of your page, you can put the graphic link to Geocities in your 'idle' frame window (ie: the one that doesn't change, for example, a menu bar), don't forget to add the 'target="_top"' to the link reference.
Also, don't forget to put links on your 'noframes' page/s as well. If you have 'noframe' pages that will also be showing in the 'frames' version, why not just add a text link back on the 'noframes' page.

GEOGUIDE

This is also a good way to link back to Geocities.
There are two types, the GeoLite (a non-java version) and the Geoguide (a java version).
To find out more about the Geoguide and how to install it on your page, visit:

LINK EXCHANGE

Why not join up with the LINK EXCHANGE.
When the banner is displayed on your site it also includes a link to Geocities.

The above icon is the basic one used for when you register to get a new home at Geocities.
If you are looking for something a bit different, visit Hazels Geocities Icons to find some links to sites that offer variations.

Also, some I have made: GeoCities/SiliconValley Icons

You can even make your own. Just grab a Graphics Program and you are on your way.

At the moment, I am in the process of making some graphics and 'Geocities' buttons for anyone who wants to use them. I don't require a link back, but if you would like to, I would be grateful and a graphic button will be available if wanted.
If you do put a link to my site on yours, I will also include your site in my reciprocal links section.