deleting files on a Mac

How do I delete a file that my Mac’s Finder thinks is “in use”?

The file could very well be in use because it’s on a shared drive, but the file really is useless, thus I don’t care if it’s “in use”. Is there a way for me to delete it manually? Do I need software?

Thanks!

ANSWER PERSON RESPONDS: Sorry for my delayed answer, but Answer Person was “in use” elsewhere.

Although I’m not currently a Mac user (I use one of Duke’s officially assigned PC’s), there seems to be a web page with information on this topic at:
http://www.thexlab.com/faqs/trash.html

It has guidance and links to trash utilities. It may not, however, apply to this shared drive issue.

You’ll have to work to paste this URL into your browswer, but here’s some interesting information:
http://www.macfixitforums.com/php/showflat.php?Cat=&Board=OfficeX&Number=678709&page=&view=&sb=&o=

It mentions some performance utilities:
Onyx: http://www.titanium.free.fr/english.html
Trash It!: http://www.versiontracker.com/dyn/moreinfo/macosx/14884