What you see under the Insert | Reference | Index and Tables menu.

Before you can use it to create a table of contents, you first have to create a set of styles. In Word 2003, you can create styles by clicking the double-A (AA) button on the Formatting toolbar, or by navigating to the Format | Styles and Formatting menu.

Once you create your new style, for top level headings (Heading 1) for example, you can highlight that text and click the New Style button on the Styles and Formatting window.

Once you have a set of styles created to your satisfaction, you can then specify which level (TOC 1, 2, 3 ?) each style will represent in your table of contents. This is accomplished by navigating to Insert | Reference | Index And Tables and then clicking the Options button on the Table Of Contents tab. On the ensuing dialog screen, you can then specify your hierarchy.

After clicking the OK button a couple of times, you will have inserted a table of contents for your document. However, you will also notice that the table is displayed in the default style. If you want to apply your custom style to the table of contents, you have one more step.

Now that you have established a set of custom styles, you can apply those styles to other parts of the document including the table of contents. Navigate To Insert | Reference | Index And Tables and click on the Modify button on the Table Of Contents tab; then click the Modify button again for each level. On the ensuing dialog screen, you can change the styles associated for each level in the hierarchy

Obviously, the styles shown are a little over the top, but the principles are the same no matter what custom styles you want to implement.