I am uploading images onto picasa and I was wondering if there's a way to show the image's tags/keywords on picasa?
Any tags you enter in Windows are stored in the EXIF data embedded within the image. Picasa will read this data automatically (and refresh it if the tags are subsequently updated) and make it available on the image's "properties" dialogue. All of the tags are also available for searching - using the search box on the main page - to filter to a set of images you are looking for.
You can also use the "tags" option (on the "view" menu) to display a dialogue which allows you to see and set the tags associated with an image (or set of images).
The tags are also displayed in the "title bar" of a selected image - the bar that displays the name, date, dimensions, size and tags of an image (the light blue bar between the main area of the screen and the bottom section that shows the "selection box" and other controls that allow quick image rotation, zoom and sharing options).