personal note -- I experimented with this and the results were crap. You're going to spend some time editing. It <might> be easier just to reset in ID. Depends on the project and how many pages you're talking.

From the InDesign CS help file:

InDesign can convert document and template files from QuarkXPress 3.3 or 4.1x. (To convert documents created with QuarkXPress 5.0 or later, reopen the documents in QuarkXPress and save them in 4.0 format.)

When you open a QuarkXPress file, InDesign converts the original file information to native InDesign information. For example:
Text is converted to InDesign text frames.

To accurately convert text wrap applied in QuarkXPress, select Text Wrap Only Affects Objects Beneath in the Composition area of the Preferences dialog box.
Styles are converted to InDesign styles.
Because QuarkXPress uses different color profiles, they are ignored in InDesign.
Text and graphics links are preserved and appear in the Links palette.

Note: Embedded graphics--those added to the original document using the Paste command--are not converted. For more information on embedded graphics, see Managing links and embedded graphics.

InDesign does not support OLE or Quark XTensions®. Consequently, when you open files that contain OLE or Quark XTensions graphics, those graphics will not appear in the InDesign document. If your QuarkXPress document does not convert, check the original and remove any objects that were created by an XTension; then save, and try to convert again.
All master pages and layers are converted to InDesign masters and layers.
All master-page objects, as well as QuarkXPress guides, are placed on the corresponding InDesign master pages.
Grouped objects remain grouped except where nonprinting items are included in a group.
All strokes and lines (including paragraph rules) are converted to the stroke styles they most closely resemble. Custom strokes and dashes are converted to custom strokes and dashes in InDesign.

Colors are converted exactly to InDesign colors, except in the following situations:
QuarkXPress 3.3 HSB colors are converted to RGB, and colors from the color library are converted based on their CMYK values.
QuarkXPress 4.1 HSB and LAB colors are converted to RGB, and colors from the color library are converted based on their RGB/CMYK values.
QuarkXPress 4.1 colors from the color library are converted based on their CMYK values.
Multi-ink colors from QuarkXPress are mapped to mixed inks in InDesign, unless the multi-ink color does not contain at least one spot color. In this case, the multi-ink color is converted to a process color instead.

To open a QuarkXPress document or template:
Make sure that the original application file is closed.

To ensure that all links are maintained, copy all linked files to the same QuarkXPress document folder.
In InDesign, choose File > Open.
In Windows, choose QuarkXPress (3.3 or 4.1x) in the Files of Type menu.
Select a file and click Open.

Note: If InDesign cannot convert a file or a specific part of a file, it displays a warning describing the reasons it cannot convert it and the results of the conversion.
If a warning dialog box appears, do one of the following:
Click Save to save a copy of the warnings as a text file, and then open the file in InDesign.
Click Close to close the dialog box and open the file in InDesign.

To save a QuarkXPress template as an InDesign template:
Open the template in InDesign.
Choose File > Save As and specify a location and filename.
Do one of the following, and then click Save:
In Windows, choose InDesign Template in the Save as Type menu.
In Mac OS, choose Stationery Option in the Format menu. Click Stationery, and click OK