Within the category browse feature you have up to 3 options for the format you view listings in. They are grid, list and gallery. You can see the buttons to change between those views within the following screenshot:
And note you can control which of those are options and which is default within your admin tool in the following locations:
SITE SETUP > BROWSING SETTINGS > Display browse view links SITE SETUP > BROWSING SETTINGS > Default Browse View
You can set a specific "body template" for each format here in the admin tool:
DESIGN > PAGE ATTACHMENT > 3_grid - Browse Categories Grid Sub-Template DESIGN > PAGE ATTACHMENT > 3_list - Browse Categories List Sub-Template DESIGN > PAGE ATTACHMENT > 3_gallery - Browse Categories Gallery Sub-Template