Hi Mike,
Yes there is ..

Querystring Parameters:
grm2catid = filter by category id
attrib = filter by attribute (list of attribute IDs separated by semi-colons)
id = filter by item id
page = display specific page #

Examples:
Assuming your Repository module is on a page with the following URL:
http://www.mysite.com/repository.aspx

Only show items in Category 3:
http://www.mysite.com/repository.aspx?grm2catid=3

Only show items with both Attribute IDs of 1 and 6
http://www.mysite.com/repository.aspx?attrib=1;6

Only show item with an ID of 123
http://www.mysite.com/repository.aspx?id=123

to determine the various IDs of the Categories and Attributes, you can look in the grmRepository... tables in the database directly, or if you have host access, you can use the SQL page and execute select statements to get the IDs

If you have any problems at all, or need more info, just ask