Updated! For the past little while I have been beta testing a new service that has now been made public. The developer, Skidz Tweak, has told me it is okay to pass along the details.
Now it is available to all, current details and links are in my Gadgets column. If you just want to see the tool, click this link. Here is why I think this new service may well replace the venerable SLURL for many of us--it certainly will for me!

Traditional SLURLs do one thing: the webpage gives you a picture of the sim with a teleport-to marker.

Sure, you can sort of get a feeling for the sim from the picture, and the teleport link will get you there. But it can be done better and the new tool I am testing is better. Here is the same sim (Agravain) in the new tool:

Yes, it is bright! More important, what you are looking at is a map of the property boundaries within the sim. See all those tiny ones! Land cutters, the rodents of the mainland, have chopped up various bits of Agravain into tiny 16 sq. meters chunks. These will either be advertising farms, or priced at ludicrous sums to extort money from neighbors.
There is more: the new tool allows some very interesting searching with a nifty search tool:

In the picture, I have searched the Agravain sim for land priced at more than L$3,000 and less than L$5,000. I get three results. Two 16 sq. meter parcels are priced at significantly more than L$200 per sq. meter! On average, mainland plots are currently changing hands at less than L$10 per square meter, so these two are what I consider to be "extortion" plots. The third result I got is a 512 sq. meter plot at a below-average price. Possibly someone desperate to escape the neighborhood.
If you are on a budget and want to find a plot of land in SL, this tool will be magic. Just enter the budget range (more than X, less than Y), leave out the sim name, and let it rip. Results are almost instant.
Another wonderful feature is an in-SL HUD that allows you to create SLURL-like links on the fly--very useful if you are posting to a blog or wiki because you can just copy and paste. The HUD tool also allows you to create folders to organize and store those links for future use.
More on this when the release happens in a few days.
Disclosure: my only involvement with this new product is as a beta tester and a happy customer of the developer's existing products.