I used to scan slides at work. All it took was a flatbed scanner and a plastic frame about 8.5 x 11 that you snap the slides into. Put it on the scanner and sacn at HIGH resolution. (1200 dpi)
If you have a flatbed scanner, you can just arrange the slides on the glass and scan. Just remember you want to scan at the highest resolution you can.
Once you have a high resolution 'contact sheet', you can clip out individual images, and blow them up, in Photoshop - or any image procesing software.
They also make slide scanners for about $100-$200: LINK