Upconversion - Processing video signal to go from lower quality input to higher quality output.
Example, Composite to S-video, Component to HDMI, S-video to HDMI, etc.
Upscaling - Processing the video signal to go from lower format input to higher format output.
Example, 480i to 480p, 720p to 1080p, 480p to 1080p, etc.
While many mid level receivers offer Upconversion, very few offer Upscaling.
Whats your budget?