iSilo™ is a highly versatile document reader available for Palm OS®, Pocket PC, Windows Mobile Smartphone, Sybmain UIQ, Symbian Series 60, and Windows® CE Handheld PC handhelds, as well as for Windows® computers. You can find thousands of ready-made documents downloadable immediately for reading with iSilo™ or you can create your own documents from HTML content using iSiloX. Some of the major features that will win you over to iSilo™ include:

High text compression in iSilo™ format documents result in a 50% to 60% decrease in size, which is about 20% better than the Palm Doc format, allowing you to store more and larger documents on your handheld.
Hyperlinks make it much easier to navigate through a document.
Images add visual richness to documents, especially photo-quality color pictures.
Tables allow the display of tabular data.
Formatted text gives style to text for controlled emphasis.
VFS support on Palm OS® allows you to store and access documents on high-capacity removeable storage

iSilo™ 5.01 for Symbian S60 3rd Edition enters beta2, adding generalized display support for devices, such as the Nokia E90, having multiple resolutions and orientations. Find it in the beta area.