I don't have Vegas Studio 4, but the full version of Vegas lets you right-mouse-button click on the time display in the upper left corner and choose various formats. Time & frames will probably do what you want. If this option isn't available you can change it in the Internal Preferences.

WARNING! Mucking about with the Internal Preferences can mess up your software installation to the point of being non-functional. Neither I nor SONY will be responsible for any problems you cause by doing this. If you get stuck, quit Vegas Studio and hold down the Shift & Control keys while you start it again. This will reset ALL preferences, including the ones you really wanted changed.

To access the Internal Preferences, click Options, then hold down Shift while clicking Preferences, then click Internal. Search for "time format" and change it to any of these values. 3 is probably the one you want.

0 - samples
1 - Time / milliseconds
2 - Seconds / milliseconds
3 - Time & frames
4 - Absolute Frames
5 - Measures & Beats
6 - SMPTE Non-Drop (29.97 Video)
7 - SMPTE 30 (30fps Audio)
8 - SMPTE Drop (29.97 Video) * default setting
9 - SMPTE EBU (25fps Video)
10 - SMPTE Film Sync (24fps, Film)

Apply, quit Vegas Studio, then start it again.

Some other handy options you might want to tweak while you're in there:
- Show Trimmer - change to TRUE
- Show Speed control - change to TRUE
- Show Advanced Features - change to TRUE

Good luck and enjoy!