Features values of typical BJT/MOS transistors
You'll probably find that articles and general discussions are more useful than selection guides at this stage. However ...

I find that using the component selector from Digikey is often useful. 

Key in the term you want information about and then work your way down the menu system.
 If you use eg "transistor" you get 12 headings under 'Discrete Semiconductor Products' and can then choose eg tansistors, bjt, single,  13842 items or FETS, single, 25,109 items.   

Selectings FETS gives you a slection table with 9 device parameters (type, feature, Rdson, Vdss, Id, Vgs(th, ), Qg, Ciss, Pmax) plus a number of other factors such as package and manufacturer.  

Selecting BJTs gives 8 parameters, some the same as for FETS and some different to reflect the difference technology. eg FETs have Vgs(th) and BJTs have Vce(sat) as only one example.



If you use [Search engine of choice] and search for eg  


mosfet selection guide  


You get a good variety of leads.
 Some are to products specific to manufacturers (still useful) and others are more general. 

As examples.

IRF (a major MOSFET manufacturer) Benchmark MOSFETs Product Selection Guide -  a nice selection guide wit 3 pages of tables. Not many parameters but good package information and a nice comparative feel.

Similar from Fairchild (the parents/grandparents of Intel, Zilog, AMD and quite  a few more) - Power MOSFET selection guide - 40 pages. They say Power but go down to eg SO8 / 1 Watt. Nice guide. Fewer parameters than you may want but useful.

ST. French. March to the beat of a different drum. But make some nice products. Online selection guide. Click the tabs and wander around.

NXP (aka Philips Gloeilampen Fabriken - old when Fairchild was born) Power MOSFETs selection guide 2011 - massively amount of very useful information but somebody had too much time on their hands. Fancy web slide flip zoom fade presentation is vastly worse than a paper page like list. Whatever. Cleverly limed to product pages and data sheets. Nice and infuriating all at once.

Hooray! Huzzah !!!
 The 2010 version of the NXP guide was not inflicted with web madness.
 NXP Power MOSFET selection guide 2010

NXP - Like unto it Power MOSFET selection guide 2009

KEC Power MOSFET selection guide 



TI MOSFET drivers



EDN A simple guide to selecting power MOSFETs. 

EE Times. The application guides the MOSFET selection process

Fairchild Selection of MOSFETS for SMPS