I just installed a ssd in my Mac mini with a 1.86GHz CPU. It was very easy, the hardest part was taking off the top. Once the ssd installed I just booted off my Snow Leopard DVD and done. What problems are you having? If you put your orignial HD into a USB enclosure you can hook it up and boot off of it first. You will see the ssd as a attached drive in Disk utility program. Format the ssd and install new OS.
If I change the CPU and add a ssd then it will max out this machine. The total cost for both is around $500-$600. It is so close to a new machine cost that I am starting to lean towards buying a new one.