It all depends on the age & build of your computer. If you are still running 98 because of your computers age then there is a good chance it will not run Vista.
Vista is going to be a very intense build and will require more then your average 4 or 5 year old factory built computer will handle.
Minimum system requirements will not be known until summer 2006 at the earliest. However, these guidelines provide useful estimates:
• 512 megabytes (MB) or more of RAM
• A dedicated graphics card with DirectX® 9.0 support
• A modern, Intel Pentium- or AMD Athlon-based PC.
Microsoft Windows Vista Beta 1 Fact Sheet http://www.microsoft.com/presspass/newsroo...staBeta1FS.mspx
If your computer meets the prerecommended spec's I would probably wait.