Here's the first little bit of the English patch for you to try out. It includes the intro of the game and the first scene between Professor Norimaki and Arale.
Here's how you install the patch on Windows:
1. Unzip the files in the attachment to this post.
2. Open the included program "Delta Patcher Lite" and click the first yellow folder icon.
3. Choose your "Dr. Slump (Japan) (Track 1).bin" file.
4. Then click the second yellow folder icon and select the included "Dr. Slump (Japan) (Track 1).xdelta"
5. If you don't want to lose your original unpatched game file, click the little gear icon next to the "Apply patch" box and click "Backup original file"
6. Click "Apply patch"!
7. Repeat steps 3-6 with "Dr. Slump (Japan).cue" and "Dr. Slump (Japan)(cue).xdelta"
If you are on a Mac platform, try the alternative to Delta Patcher here: http://www.romhacking.net/utilities/746