Yes, you can definitely do it. It would look like something like this:
ReportService.ReportingService rs = new ReportService.ReportingService();
rs.Credentials = System.Net.CredentialCache.DefaultCredentials;
rs.Url = "http://localhost/reportserver/reportservice.asmx";
ReportService.CatalogItem[] items = rs.ListChildren("/TestReports", true);
for (cnt = 0; cnt <= items.Length - 1; cnt++)
{
listBox1.Items.Add(items[cnt].Name.ToString());
}