I just wanted to know how you limit the people who can browse your host. I still want to share my files but when I check on my uploads, there are many users 'without smiley faces' next to them. Can I change the settinggs so that it is just those users that are able to connect?

Just because a Limewire user has a smiley icon next to their avatar does not necessarily mean that they are 100% good suppliers or takers of files.
Use your judgement and don't download programs or games without making sure you have a good Antivirus program to check the files as they arrive.
Personally I never use Limewire to download files with the extensions .exe, .rar or .zip.
I only ever use Limewire for music files and even then I am very careful and make sure my AV program is monitoring the download to make sure the file does not contain a virus or other form of malware.