Question : will timesheets work in sharepoint

When implementing a time sheet solution across a 500-staff userbase, with addional requirement for resource management tools + project task tracking, wiil SharePoint suffice, or is installation of Project Server necessary

Answer : will timesheets work in sharepoint

100% doable, and every bit of it by the front end only. Wish I could send you my stuff, but they are far too heavily customized. The best place for you to look right now is through the Microsoft Sharepoint Templates. You can find the entire pack linked below. A number of them will do exactly what you want. You will obviously need to spend a lot of time on configuration.

http://www.microsoft.com/downloads/details.aspx?FamilyID=5807b5ef-57a1-47cb-8666-78c1363f127d&DisplayLang=en