it seems I've got some solution for viewing PDF on kindle 3 device.
1. First of all open PDF with Adobe Acrobat (not Adobe Reader). You can get Trial version of Acrobat from Adobe website.
2. Save PDF as a full HTML page - this will rasterize all vector images, graphs etc. which are saved in images folder (this will be used later on)
3. Import HTML to Mobipocket creator
4. After importing Mobipocket has created new folder somewhere like .../Documents/My Publications/"newlyCreatedFolder"
5. Copy "images folder" which was created by Acrobat into the "newlyCreatedFolder" folder created by Mobipocket
6. Click on Build button in Mobipocket
7. wait for your converted ebook and upload it onto your kindle device
One drawback of this solution is, that there are no chapter signs - so you cannot skip chapters using buttons on your device
Anyway you can change the size of the text, which is great